How to Add an Email Signature in Apple Mail (Mac, iPhone, iPad)

An Apple Mail email signature is a reusable block of text, images, and links that automatically appears at the bottom of every email you send from Apple's built-in Mail app. It functions as a digital business card, displaying your name, title, contact details, and branding across macOS, iOS, and iPadOS devices.

According to Litmus, Apple Mail holds approximately 58% of email client market share as of 2025, making it the most widely used email platform in the world. Whether you are sending from your Mac, iPhone, or iPad, a well-configured signature ensures every message looks polished and professional.

This guide covers everything you need to know: creating signatures on each Apple device, adding HTML designs, troubleshooting common rendering issues, and best practices for professional results.

What Is an Apple Mail Email Signature?

An email signature in Apple Mail is a customizable text block appended to your outgoing messages. Unlike some email clients that offer built-in design editors, Apple Mail relies on a plain text or rich text editor on Mac and a basic text field on iOS and iPadOS. This means advanced designs, such as those with logos, social icons, or styled layouts, typically require pasting HTML code directly into the signature file.

Apple Mail signatures sync across devices when you use iCloud, so a signature created on your Mac can appear on your iPhone and iPad. However, HTML signatures created using the file-editing method on Mac do not sync automatically and must be configured separately on each device.

Apple Mail signature size limit: Apple does not publish an official character or file-size limit for signatures. In practice, signatures under 10KB render reliably across all Apple devices. Signatures larger than 30-40KB, especially those with embedded Base64 images, may be stripped or distorted by recipient email clients. Use externally hosted images to keep file sizes small.

How to Add a Signature in Apple Mail on Mac

Setting up a signature on macOS takes just a few steps. Apple Mail supports both plain text and rich text signatures natively.

Step 1: Open Mail Preferences

1. Open the Mail app on your Mac
2. Click Mail in the menu bar, then select Settings (or Preferences on older macOS versions)
3. Click the Signatures tab

Step 2: Create a New Signature

1. In the left column, select the email account you want the signature for, or choose All Signatures to make it available across accounts
2. Click the + button at the bottom of the middle column
3. A new signature appears with the default name "Signature #1" - click the name to rename it (e.g., "Work" or "Personal")

Step 3: Write Your Signature Content

1. In the right panel, type your signature content
2. Use the Format menu to apply basic styling: bold, italic, font size, and color
3. Include your essential details:
   • Full name
   • Job title
   • Company name
   • Phone number
   • Email address
   • Website URL

Step 4: Assign the Signature

1. Drag the signature from the middle column to the email account in the left column
2. At the bottom of the window, use the Choose Signature dropdown to set your default signature
3. Select from: your named signature, "None," or "At Random" (if you have multiple signatures)

Step 5: Verify It Works

1. Close Settings and compose a new email
2. Your signature should appear automatically at the bottom
3. Send a test email to yourself to confirm formatting

Pro tip: Uncheck "Always match my default message font" at the bottom of the Signatures tab if you want your signature to keep its own font styling instead of adopting your compose font.

How to Add a Signature in Apple Mail on iPhone and iPad

iOS and iPadOS use a simplified signature editor that supports plain text only. Here is how to set one up.

iPhone

1. Open the Settings app
2. Scroll down and tap Mail
3. Tap Signature (near the bottom of the Mail settings)
4. Choose All Accounts to use one signature everywhere, or Per Account to customize each
5. Type your signature text in the field
6. Tap back to save automatically

iPad

The process on iPad is identical to iPhone:

1. Settings > Mail > Signature
2. Choose All Accounts or Per Account
3. Enter your signature text
4. Navigate back to save

Mobile Signature Limitations

The iOS and iPadOS signature editor does not support:

• HTML formatting
• Images or logos
• Clickable hyperlinks (URLs appear as plain text but may auto-link)
• Font styling beyond the system default

For a richer mobile signature, you have two options: use a tool like Signkit's email signature templates to generate a mobile-optimized signature, or set up an HTML signature on Mac and sync it via iCloud (results may vary).

How to Create an HTML Signature in Apple Mail

Apple Mail does not have a built-in HTML editor, but you can add custom HTML signatures using the copy-paste method on Mac. This is the most reliable approach for professional signatures with logos, icons, and styled layouts.

Method: Copy and Paste from Browser

1. Design your signature using an online tool or create your signature with Signkit
2. Open the signature in a web browser so it renders as styled HTML
3. Select the entire signature in the browser (Cmd+A or click and drag)
4. Copy it (Cmd+C)
5. Open Mail > Settings > Signatures
6. Create a new signature or select an existing one
7. Click in the signature preview panel and select all existing content (Cmd+A)
8. Paste (Cmd+V) - the styled HTML should appear with formatting intact

Important Notes on the Copy-Paste Method

• You must copy from a rendered browser view, not from raw HTML code
• Images must be hosted online (use absolute URLs starting with https://)
• Apple Mail may strip some CSS properties on paste
• Uncheck "Always match my default message font" to preserve your custom styling
• Test by sending an email to yourself and checking on multiple devices

According to a Radicati Group study, professionals send an average of 40 emails per day. With that volume, even small improvements to your signature's design compound into significant brand exposure over time.

What to Include in Your HTML Signature

Element	Recommended	Notes
Full name	Yes	Bold, slightly larger font
Job title	Yes	Regular weight
Company name	Yes	With link to website
Phone number	Yes	Use tel: link for mobile tap-to-call
Logo	Optional	Host externally, max 200px wide
Social icons	Optional	Limit to 2-3 platforms
Banner/CTA	Optional	Great for promotions or events

Apple Mail Signature Best Practices

Keep It Under 6 Lines

Long signatures push your message content down and look cluttered in email threads. Stick to name, title, company, phone, and one link. If you need more, use a two-column table layout with your logo on the left and text on the right.

Use Web-Safe Fonts

Apple Mail renders custom fonts well on Apple devices, but recipients using Outlook, Gmail, or other clients may see fallback fonts. Stick with Arial, Helvetica, Verdana, or Georgia for maximum compatibility.

Host Images Externally

Never embed images as Base64 data in your signature. Instead, host logos and headshots on your company website or a CDN and reference them with absolute https:// URLs. This keeps your signature file small and ensures images load reliably.

Optimize for Dark Mode

Apple Mail supports dark mode on both macOS and iOS. To avoid your signature looking broken in dark mode:

• Use transparent PNG logos instead of JPGs with white backgrounds
• Avoid pure white (#FFFFFF) backgrounds in signature tables
• Test your signature in both light and dark mode before deploying

Make Contact Info Actionable

• Phone numbers should use tel: links so mobile users can tap to call
• Email addresses should use mailto: links
• Website URLs should be full hyperlinks, not plain text

For more design guidance, see our email signature design best practices.

Common Apple Mail Signature Issues and Fixes

Signature Looks Different When Received

Problem: Your signature looks perfect in Apple Mail but appears broken or unstyled when recipients open it in Outlook or Gmail.

Solution: Apple Mail uses WebKit rendering, which is more permissive than other email clients. Use table-based HTML layouts instead of CSS positioning. Inline all styles directly on HTML elements rather than using <style> blocks. Test your signature by sending to Gmail, Outlook, and Yahoo accounts.

Images Not Displaying

Problem: Logo or headshot shows as a broken icon or blank space.

Solution: Verify that image URLs are publicly accessible (not behind a login). Use https:// URLs only. Keep image files under 50KB. Some corporate email servers block external images by default - this is on the recipient's end and cannot be controlled from your side.

Signature Disappears After macOS Update

Problem: After updating macOS, your HTML signature reverts to plain text or vanishes.

Solution: macOS updates can reset Mail signature files. Keep a backup of your HTML signature. After an update, recreate the signature using the copy-paste method described above. Alternatively, use a signature management tool like Signkit to re-deploy signatures instantly.

Extra Line Spacing in Signature

Problem: Apple Mail adds unwanted blank lines above or below your signature.

Solution: In Mail Settings > Signatures, check whether "Place signature above quoted text" is enabled. Extra spacing can also come from empty <p> or <br> tags in your HTML. Clean up your HTML to remove any trailing whitespace or empty elements.

Signature Not Syncing Across Devices

Problem: Signature created on Mac does not appear on iPhone or iPad.

Solution: Basic text signatures sync via iCloud if you are signed into the same Apple ID and have Mail enabled in iCloud settings. HTML signatures created via file editing do not sync. For consistent cross-device signatures, set up your plain text version separately on each device, or use a centralized signature management tool.

Frequently Asked Questions

How do I add an HTML signature in Apple Mail?

Apple Mail does not include a built-in HTML editor for signatures. The most reliable method is to design your signature in a web browser or tool like Signkit, select and copy the rendered output from the browser, then paste it into the Mail signature editor on Mac (Mail > Settings > Signatures). This preserves formatting, images, and links. Make sure to uncheck "Always match my default message font" to keep your custom styling.

Why does my Apple Mail signature look different when received?

Apple Mail uses WebKit to render signatures, which supports modern CSS properties that other email clients do not. When your email is opened in Outlook, Gmail, or Yahoo Mail, unsupported CSS is stripped, causing layout shifts. To prevent this, use table-based HTML layouts with inline styles, stick to web-safe fonts, and test your signature by sending it to accounts on different email platforms before deploying it.

Can I have different signatures for different email accounts in Apple Mail?

Yes. In Apple Mail on Mac, go to Mail > Settings > Signatures. The left column lists all your email accounts. You can create signatures under "All Signatures" and then drag them to specific accounts. Each account can have its own default signature selected from the dropdown at the bottom of the window. On iPhone and iPad, go to Settings > Mail > Signature and select "Per Account" to customize each one individually.

How do I add an image or logo to my Apple Mail signature?

On Mac, the easiest method is to design your signature with a logo in a web browser, then copy and paste the rendered result into the Mail signature editor. The logo image must be hosted online with a public https:// URL. You can also drag an image file directly into the signature editor, but this embeds the image, increasing your email size. Hosted images are strongly recommended.

Does Apple Mail support rich text signatures on iPhone?

No. The iPhone and iPad signature editor only supports plain text. You cannot add images, links, or formatted text directly through Settings > Mail > Signature. However, if you create a rich text or HTML signature on your Mac and it syncs via iCloud, it may carry over to your iPhone in some cases. For reliable rich signatures on mobile, use a signature management tool that generates mobile-optimized HTML.

Key Takeaways

• Mac signatures support rich text natively: Use Mail > Settings > Signatures to create and assign signatures with basic formatting, or paste rendered HTML from a browser for advanced designs.
• iPhone and iPad are plain text only: The iOS signature editor does not support HTML, images, or formatted text. Set up signatures in Settings > Mail > Signature.
• Host images externally for reliability: Use public https:// URLs for logos and headshots instead of embedding them. This keeps email size small and avoids broken images.
• Test across email clients before deploying: Apple Mail's WebKit rendering is more permissive than Outlook or Gmail. Always send test emails to verify your signature looks correct everywhere.
• Use a signature management tool for teams: For consistent branding across multiple employees and devices, tools like Signkit let you design once and deploy everywhere without manual setup on each device.