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How-to guide

How to add a signature in Apple Mail (Mac)

Apple Mail signatures are easy — until you want your logo and formatting to survive. Here's the full path, traps included.

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Step by step

  1. In Mail: menu bar → Mail → Settings (⌘,) → Signatures tab.
  2. Select your account in the left column, click +.
  3. Paste your signature (from a generator or browser) into the right pane.
  4. Untick “Always match my default message font” — the #1 reason signatures lose their design.
  5. Drag the signature from the middle column onto the account, then pick it under Choose Signature → default.
  6. Compose a new message to verify images and links.

Keeping images intact

Apple Mail displays pasted images, but the safest signatures reference hosted HTTPS images (your logo served from the web) rather than embedded files — recipients on Outlook and Gmail then see exactly what you see. Signatures built in ProSignature use hosted assets and inline styles for this reason.

Where signatures live, and the checkbox that ruins them

In Apple Mail on macOS, signatures are under MailSettings (called Preferences on older macOS versions) › the Signatures tab. The window has three columns: your accounts on the left, the signatures for the selected account in the middle, and the editor on the right. A signature must be created while the correct account is selected — or dragged onto that account afterwards — or it will not be offered when composing from that address.

Beneath the editor sits the setting that causes most Apple Mail signature complaints: “Always match my default message font”. With it ticked, Apple Mail strips your signature's fonts, sizes and colours and renders everything in the composing font — so a carefully branded signature arrives as flat, uniform text. Unticking it is the fix, and it is the first thing to check when a pasted signature looks wrong.

Pasting an HTML signature reliably

  1. Copy the signature from its source — a generator that outputs email-safe HTML, or a browser window where it is rendered.
  2. Open Mail › Settings › Signatures and select the correct account on the left.
  3. Click + to create a signature, then clear whatever placeholder text Apple Mail inserts.
  4. Paste. Then untick “Always match my default message font” — otherwise the formatting is stripped on send.
  5. Close Settings and compose a test message to yourself to confirm it renders and the links work.

Images, syncing and the quirks worth knowing

Images should be hosted, not dragged in

Dragging a local file embeds it, which can arrive as an attachment. A hosted, correctly sized image is more reliable — see the image size guide.

Signatures do not sync unless iCloud does

Apple Mail signatures live on the Mac. They travel between your own devices only if iCloud Drive syncing covers Mail, and they never travel to a colleague's machine.

Per-account assignment is easy to miss

A signature created with the wrong account selected simply will not appear for the address you wanted.

Choose the default per account

The dropdown at the foot of the Signatures pane sets which signature is used automatically for each address.

Written and maintained by the ProSignature team. Competitor pricing and feature claims on this site are verified against each vendor's live page on the day of writing — last verified 26 July 2026. No affiliate links. How we work.

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FAQ

Frequently asked questions

Why did my signature lose its fonts?

The 'Always match my default message font' checkbox overrides your design — untick it in the Signatures tab.

Why do images arrive as attachments?

Embedded images are attached files. Use a signature whose images load from a hosted HTTPS URL instead.

Does the Mac signature sync to my iPhone?

Only via iCloud accounts, and imperfectly. Set the iPhone signature separately, or manage the signature at the provider level (e.g., Gmail settings).

Can I have per-account signatures?

Yes — each account in the Signatures tab holds its own list; drag signatures between accounts to share them.

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