click the settings icon (the gear) on the top right of the screen.

Click the "Mail" option on the left and then the "Compose and reply" option. You can then begin to compose your signature(don't forget to name it). To set your Legacyinc.com signature, visit 2024 Email Signature Update (Webmail) - Google Docs for the template.

Once complete, click "Save" in the lower right corner and under "Select default signatures" set both to the name of the new signaturet. This will add the signature automatically when creating emails.