How to create multiple signatures using canned responses
You can create multiple signatures for different types of emails with Gmail's canned responses.
How to do it:
Enable canned responses
Step 1: Go to Gmail, click Settings icon and select Settings.
Step 2: At the top, select the Labs tab.
Step 3: In the Canned Responses section, select Enable.
Step 4: At the bottom, click Save Changes.
Create canned response signatures
Step 1: Go to Gmail, click COMPOSE.
Step 2: In the New Message window, type and format your signature.
Step 3: In the bottom-right corner of the Compose window, click the Down arrow and select Canned responses > New canned response.
Sep 4: Enter a name for the canned response signature and click OK.
Step 5: Continue composing and send your message, or close the compose window to use your signature another time.
Send email with canned response signatures
Step 1: Go to Gmail, click COMPOSE and compose your message.
Step 2: In the bottom-right corner of the Compose window, click the Down arrow , select Canned responses, and choose a saved signature canned response to insert in your message.
Step 3: Click Send.