Add your signature to Apple Mail

⏱ About 90 seconds · macOS

1. In the OnceSig editor, click “Copy signature”.
2. Open Mail, then Mail → “Settings…” (⌘,) → “Signatures” tab.
3. In the left column, select the email account the signature belongs to.
4. Click “+” to create a signature and give it a name.
5. Important: uncheck “Always match my default message font”.
6. Click into the signature area and paste with ⌘V.
7. Close the settings window — Mail saves automatically. Pick the signature in the “Signature” dropdown when composing, or set it as default below the list.

Good to know

• Images may look broken in the settings pane — Mail's signature preview sometimes shows a placeholder where your photo is. Send yourself a test email; it renders correctly in the actual message.
• iPhone/iPad Mail is separate and only supports basic signatures. Your desktop signature still displays in full for everyone you email from the Mac.
• iCloud accounts sync signatures across Macs; other account types keep them per-machine.