how do I change my Apple ID

Please read this link -->

Change your Apple ID - https://support.apple.com/HT202667 - "Follow these steps to change the email address that you use as your Apple ID." Plus special instructions if your Apple ID ends with @icloud.com, @me.com, or @mac.com. You may also wish to turn off "Find My" before changing information and turn it on again afterward.

"After you change your Apple ID email address or password, you might need to update your sign-in information with any Apple services you're using" Click on this link to read "What to do after [or before] you change your Apple ID email address or password" --> https://support.apple.com/HT204071

- This is particularly important to do if you use the "Find My" feature. Disable Find My before changing your information, change the information, then reactivate it with the new information.

To turn Find My on and off:

For devices with iOS12 and earlier, or Macs with Mojave or earlier read this link on how to Set up Find My iPhone on all of your devices" - https://support.apple.com/HT205362

Home screen > Settings > [your Apple ID] > iCloud > Find My > turn on/off

For devices with iOS 13 or later, or Macs with Catalina or later read this on how to "Set up Find My on your iPhone, Mac, AirPods, or other devices" - https://support.apple.com/HT210400

[mobile devices:] How to turn on/off Find My for your iPhone, iPad, or iPod touch

Home screen > Settings> Name > Find My > on/off