When you trying to login Gmail on web browser like Chrome, you will find number of saved Gmail accounts on the computer browser. This is the easiest way to remove saved Gmail accounts from computer. Just below the saved Gmail accounts on the browser you will find an option called remove an account.
Tap on remove account, then you need to click on the minus symbol, it will ask the confirmation to delete or remove the saved Gmail account from the browser.
Confirm to remove the Gmail account from the browser.