I could not find anything on signatures in gmail help but I found a link to a forum. A general Google search also turned up somebody's post on the subject. To sum up what I learned.
Go to settings top right of your gmail screen, it is a cogwheel, meaning circular, a ring, with battlement or square edges
click
scroll down
go to signatures -
make changes
save
see default to set it
For more detail see
When hunting for advice or specific web pages, the magic search words include e-signature and digital signature.
Useful Websites
Wiki on electronic signature
https://en.wikipedia.org/wiki/Electronic_signature
Gmail Forum
https://support.google.com/mail/answer/8395?hl=en&co=GENIE.Platform=Desktop
Internet post
https://www.wisestamp.com/guides/how-to-add-signature-in-gmail/
https://www.wikihow.com/Create-a-Professional-Email-Signature
Download and buy signature Systems
https://www.hellosign.com/esignatures?utm_medium=cpc&utm_source=google&utm_campaign=HS-NonBrand-eSignature-US&utm_content=hs-nonbrand-esignature-us_online-signature&utm_term=%2Bonline%20%2Bsignature&utm_matchtype=b&gclid=CjwKCAjw8cCGBhB6EiwAgORey3N7A1C45Qu9TYVogprlw2kbfc028mzf8MZWKvPAUiJAtIdFHxeCvRoC290QAvD_BwE
Angela Lansbury teacher of English (advanced and English as a Second Language or English as a Foreign Language, French and other languages, aspiring polyglot.