A Gmail signature can be inserted automatically into new messages and replies, but those two defaults should be checked separately. Start with a short, readable signature and verify the account and sending address before making it the default.
Create the signature in Gmail on the web
- Open Gmail on a computer and go to Settings → See all settings.
- Under General, find the Signature area and create or select a named signature.
- Enter the contact details you want recipients to receive. Apply the available formatting only where it improves readability.
- Choose the appropriate signature default for new messages and the default for replies or forwards.
- Save changes at the bottom of the settings page.
Google permits up to 10,000 characters and notes that an image counts toward the limit. That is a ceiling, not a recommended length. A name, role, appropriate contact method, and necessary business details are often easier to maintain than a large promotional footer.
Test both message types
Open a fresh message and confirm that the intended signature appears once. Then open a reply and check its signature independently. A default selected for new mail does not establish that the reply default is also correct.
Where multiple authorized sending addresses are configured, inspect the selected From address as well. A signature is ordinary message content; it does not itself change the sender identity or verify your ownership of another address.
Check the result outside the editor
Send a harmless test to yourself and open it on a small screen. Confirm that telephone numbers, email links, and website links lead to the intended destinations. Avoid putting private personal information into a footer attached to every message.
Keep a copy of your approved wording before experimenting with images or complex pasted formatting. If a recipient sees a broken image, resolve that image’s access and size separately rather than repeatedly adding the signature to the same draft.
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References
Reviewed against the linked official and developer guidance on October 27, 2026. Available options and screen labels can vary by account, device, region, and organization policy.