Apple id

How to Change Your Apple ID

[Originally posted by donv (The Ghost).]

1. Change your Apple ID (Be very aware of the restrictions here.) 
2. Before changing your Apple ID using a computer, sign out of all Apple  services that use your Apple ID. If you are going to use an iPhone, iPad, or iPod, then stay signed in with your Apple ID on only that device. This instruction is taken from the above document under the heading Before you change your Apple ID.
3. For sign out purposes, see Where can I use my Apple ID? “This list is provided for informational purposes only and is subject to change without notice. It's not intended to include every feature or service that uses Apple ID. Visit the Apple ID support page for more information.”
4. There may be some redundancy, but see What to do after you change your Apple ID or password.

(I have done minor editing to improve presentation.)

You can take this approach:

First, use What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch https://support.apple.com/en-us/HT201351to return the phone to factory fresh.

Then, use Set up your iPhone, iPad, or iPod touch https://support.apple.com/en-us/HT202033 using the chosen Apple ID.

__________

But, you also could create a new Apple ID this way:

See How to create a new Apple ID https://support.apple.com/en-us/HT204316  and

How to switch Apple IDs on your iPhone or iPad

https://www.imore.com/how-change-apple-id-your-iphone-or-ipad

See the data implications below.

Some of these things may apply even though not changing an Apple ID: What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071

 Keep in mind that some things available under a first Apple ID will not be available under a new Apple ID. For example, you won’t be able to transfer anything purchased from the App and iTunes Stores to the new ID. And, there are other issues to be addressed.

And see what Eric Root says on this matter here  https://discussions.apple.com/thread/251483565 and

what Winston Churchill says about it here: https://discussions.apple.com/thread/7452747

__________

But, despite any other data loss you can set up family sharing between the IDs to share purchases made with them. See:

Family Sharing  https://support.apple.com/en-us/HT201060

Set up Family Sharing https://support.apple.com/en-us/HT201088