How do you transfer an gmail account from my mac to somebody else

Just remove the account from the Mac, and give them the credentials (email address and password) and they can set it up on their computer.

If using the default Mail App:

1. In Mail, from the Mail menu, select Preferences....
2. Click Accounts, and then highlight the account you want to delete.
3. Click - (the minus sign).
4. When prompted, click Remove or OK, and then close the Mail preferences window.

There may be a better way for someone else to have a google mail gmail account

because there are several items in an account that relate to the creator that may

not be suited for someone else; or if the second owner poses as the original, etc.

Create your Google Account

A single username and password gets you into everything Google (Gmail, ... Create

your Google Account ... One free account gets you into everything Google.

https://accounts.google.com/SignUp?hl=en-GB

Sign-in & security - Google Account

Every Google Account comes with today's most advanced security features built in.

Sign in to see if your security settings are up to date.

https://myaccount.google.com/intro/security

Unless you know and trust the individual or unless they already had been sharing,

the unlikely prospect or necessity of handing off an existing account is about nil.

{..As a 20 year account holder, the rules have and do change ~ read them first..}