An email Signature is text, image like your contact information that is added automatically at the end of the email messages as a footer. This is known as Email Signature.
ADD OR modify a mail signature [In the Computer]:
Steps 2. Click on See All Settings.
Steps 3. Within the general tab, below find the Signature section. Click on create new
Steps 4. Then write Signature name then create your Signature.
Steps 4. At the below of the page, click Save Changes.
ADD OR modify a mail signature [In the Android]:
Steps 1. Open the Gmail app on your mobile phone.
Steps 2. At the upper left corner, tap Menu then at the bottom tap Settings.
Steps 3. Select the google account in which you want to add a Signature.
Steps 4. Tap the mobile signature to add the signature.
Steps 5.Click on Mobile Signature then write your desired Signature.
Steps 6. Click Ok to save the signature.