How to Set Up an Email Signature in Apple Mail (Mac & iPhone)

Apple Mail is the default email client on Mac and iPhone. Setting up a basic text signature takes about 30 seconds. Getting a rich HTML signature to work takes a bit more effort. Here is how to do both.

macOS: Basic Signature Setup

Open Mail on your Mac. Go to Mail > Settings (or Mail > Preferences on older macOS versions). Click the Signatures tab.

You will see three columns: your email accounts on the left, signatures in the middle, and a preview/editor on the right. Click the + button in the middle column to create a new signature.

Type your signature text directly in the editor. You can apply basic formatting: bold, italic, font changes, and colors. For most people, this is sufficient. Set the signature as default for the relevant email account using the dropdown at the bottom.

macOS: HTML Signature (The Workaround)

Apple Mail does not have an "Import HTML" button. But there is a workaround that has worked reliably for years:

Step 1: Create a placeholder signature

In Mail > Settings > Signatures, create a new signature with any placeholder text (even just "temp"). Close Mail completely.

Step 2: Find the signature file

Open Finder and go to: ~/Library/Mail/V10/MailData/Signatures/ (the V10 folder may be V9, V8, etc., depending on your macOS version). Look for a .mailsignature file with a recent modification date. That is your placeholder.

Step 3: Edit the file

Open the .mailsignature file in a text editor (TextEdit in plain text mode, or VS Code). You will see a MIME header at the top followed by basic HTML. Keep the header lines intact. Replace everything after the header with your custom HTML signature code.

Step 4: Lock the file

Save the file. Then right-click it in Finder, select Get Info, and check the Locked checkbox. This prevents Mail from overwriting your custom HTML the next time it opens.

Step 5: Reopen Mail and test

Open Mail. Compose a new email and select your signature. It should now render your custom HTML. Send yourself a test to verify it looks correct.

This method works but it is fragile. macOS updates sometimes reset signature files, and you will need to repeat the process. If you want something more robust, use EmailSign to generate a signature and follow the same paste method with properly optimized HTML.

iOS: iPhone & iPad Signature

On your iPhone or iPad, go to Settings > Apps > Mail > Signature(on older iOS: Settings > Mail > Signature).

If you have multiple email accounts, toggle Per Account to set different signatures for each one. Type your signature in the text field.

Here is the limitation: iOS Mail's signature field is plain text only. No formatting, no images, no links (unless you type the full URL). This means your carefully designed HTML signature from your Mac will not carry over to your iPhone.

The iOS workaround

There is a partial workaround:

• Open your HTML signature in Safari on your iPhone
• Select all the content (long press, then "Select All")
• Copy it
• Go to Settings > Mail > Signature
• Paste into the signature field

This sometimes preserves basic formatting and links. Results vary by iOS version and signature complexity. Simple signatures (text with a few links) usually work. Complex table-based layouts often break.

Tips for Apple Mail Signatures

• Keep it simple on mobile: Accept that your iPhone signature will be simpler than your desktop one. A clean text signature with your name, title, and phone is better than a broken HTML layout.
• Test dark mode: Apple Mail has aggressive dark mode rendering. Light background colors get inverted. Test your signature in both light and dark mode. Avoid pure white backgrounds in your HTML.
• Image hosting matters: Apple Mail loads remote images by default (unlike Outlook). But if your image URL is HTTP (not HTTPS), it may be blocked. Always use HTTPS.
• Retina images: Mac screens are high-DPI. If your logo looks blurry, you are probably using a 1x image. Use a 2x resolution image and set the display width via HTML attributes. See our size guide for specs.

Other Email Client Guides

Not just using Apple Mail? We have setup guides for Gmail and Outlook too. Or skip the manual setup entirely and use the EmailSign builder to create a signature that works across all three clients.