Email signature generator › Apple Mail signature

How to add an HTML signature in Apple Mail

Apple Mail is the awkward one: there is no field for HTML. Two routes work — one simple, one that edits the signature file directly.

Method 1 — paste the rendered signature (works for most people)

1. Copy your signature from the generator above with Copy signature. This puts the rendered signature on the clipboard, not the code.
2. In Mail, open Settings → Signatures.
3. Select the account on the left, click + to add a signature, and name it.
4. Uncheck "Always match my default message font" — this is the step everyone misses, and leaving it checked flattens the signature to plain text.
5. Select any placeholder text in the box and paste over it.
6. Close the window. Mail saves as you go.

Method 2 — edit the signature file (full control)

If the paste route mangles the layout, the signature can be written directly to disk. Mail stores each signature as a .mailsignature file.

1. Create a signature in Mail with any placeholder text, such as the word PLACEHOLDER, then quit Mail completely.
2. In Finder press Cmd + Shift + G and go to ~/Library/Mail/V10/MailData/Signatures. The version number changes with the macOS release, so use whichever V folder exists.
3. Find the .mailsignature file containing your placeholder — sort by date modified and it is the newest.
4. Open it in TextEdit. Keep the header lines at the top intact and replace everything after them with your signature HTML.
5. Save, then lock the file: right-click → Get Info → tick Locked. Without this, Mail overwrites your edit.
6. Reopen Mail.

iPhone and iPad

iOS Mail has no HTML signature field. Settings → Apps → Mail → Signature accepts styled text only — bold, italic, a link — not a table layout.

The workable trick: email the signature to yourself from your Mac, open it on the phone, select it, copy, then paste into the signature field. Some formatting survives, images usually do not. For a signature that is genuinely identical everywhere, the only reliable answer is a server-side signature applied by your mail provider.

Per-account signatures

Mail assigns signatures per account, which is handy if you run more than one address. Select the account in the left column before adding, and set Choose Signature at the bottom to pick the default for that account.

If a signature appears under All Signatures but not under a specific account, it has not been assigned: drag it from the middle column onto the account name on the left. This catches almost everyone at least once, because the drag is the only way to do it.

iCloud sync makes edits reappear

If iCloud Drive has Mail enabled, signatures sync across your Apple devices — which is convenient until you edit the file by hand. iCloud can push the old version back over your edit minutes later, making it look as though the change never saved.

If you are using the file-editing method above and the signature keeps reverting, turn off Mail syncing in System Settings → Apple Account → iCloud → iCloud Drive → Options while you work, then decide whether you want it back on. Locking the file, as described above, is the lighter-touch fix and usually enough.

Check it before you trust it

Apple Mail is the client most likely to render a signature correctly in its own compose window and incorrectly on arrival, because the compose view uses a different rendering path from the message it sends. So the only meaningful test is a real one:

1. Send a message to an address on another provider — a Gmail account works well.
2. Open it there, in the browser, and check the layout and the logo.
3. Open the same message on your phone.

If it survives those three views it will survive almost anything. If it looks right in Mail's compose window only, the signature is not actually working yet.

Frequently asked questions