How to set up a new email address

With what provider?

If you already have one and want to know how to add it to your device:

Add an email account to your iPhone, iPad, or iPod touch - Apple Support

bluize4me2 Said:

"How do I set up a new email address?"

-------

iCloud:

If you are asking about iCloud, then note that you can only use one for iCloud. It cannot be changed.

Use a New App Password:

Do you use an App Password? If so, try a new App Password. Sometimes, changes (i.e. updates) are made to the MacBook, and then mail server syncing becomes an issue (which is what a new App Password is intended to fix). For example, go here for gmail: Sign in with App Passwords - Google Account Help - Google

bluize4me2 Said:

"I want to add a new (additional) iCloud email address to what I already have. How do I do this?"

-------

You Cannot. And note that as of this post, Apple Accounts cannot be merged. It all has to do with licensing between Apple and the Studio or Developer.