If you want to update any application setting within your Apple computer the default move is to click the Name of the application in the upper left and click “Preferences”. In Apple Mail, it just says “Mail”.
So let’s say you want to add a new Gmail account to your computer. You would click on Mail > Accounts. HOWEVER, this actually takes you to your computer’s System Preferences > Internet Account settings (same as if you would have clicked the in the upper left and selected “System Preferences”). Once here you are adding the account as a computer-wide “internet account”. Pretty straight forward, simple to do and will now be available as an account in other applications like iCal and iMessage.But what if you want to rename HOW the account appears in the dropdown when you’re composing an email or change the From name that shows up? If you navigate back to Mail > Accounts you’re going to get pretty frustrated. For this effort, you actually want to go to Mail > Preferences > Accounts. There are actually 2 different “Accounts” options that do entirely different things! Once here you can dig in and get more granular with the Description of your account, specific email server settings and how you want to handle things like drafts or junk mail, etc.
In this area (Mail > Preferences), you can also do things like update your Signature(s), create different mail Rules or even change/set your Fonts & Colors.
The one thing we love about Apple is there is usually a simple setting somewhere to change to dial in our devices to exactly what we want, you just have to know how to get there.