How to change email address?

Here's how you change the email address you use for your Apple ID:

1. Go to https://appleid.apple.com and sign in.

2. In the Sign-In and Security section, choose Apple ID.

3. Enter the email address that you want to use as your Apple ID.

4. Choose Change Apple ID.

5. If you changed your Apple ID to a third-party email address, check your email for a verification code, then enter the code. Learn what to do if you didn't get the email. --> If you didn't receive your verification or reset email - Apple Support

6. If you use services like iCloud or Messages to share with friends and colleagues, sign in to those services with your updated Apple ID. --> What to do after you change your Apple ID or password - Apple Support

For more details, read the document: "Change your Apple ID" --> Change your Apple ID - Apple Support

Unfortunately Apple doesn't have a document about reusing email addresses.

From: Change your Apple ID - Apple Support

"If you see a message that the email address you want to use isn't available or is already in use, check that you or a family member aren't already using that email address with a different Apple ID. If a family member is using that email address, remove it from their account then try to use it."

Although this next section discusses email address re-use in the context of deleting an account, it supports observations frequently posted on this forum about not being able to re-use an email address as an Apple ID once used previously as an Apple ID:

From: How to delete your Apple ID account - Apple Support

"Can I use the primary email address for my deleted Apple ID account to create a new Apple ID or with another existing Apple ID account?

No, once your Apple ID is deleted, you can't use the email address that you used with it to create a new Apple ID. In addition, you can't use that email address with another existing Apple ID except as a rescue [notification] email. Also, if your primary Apple ID email address is with a Custom Email Domain, it can never be reused to create an Apple ID after your Apple ID is deleted, even if the domain ownership changes."

If you still have questions or problems:

Refer to this document for ways to contact Apple --> Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone --> Contact Apple for support and service - Apple Support