Use a different Apple Account to share purchases with Family Sharing
If you have more than one Apple Account and you want to use a different one to share purchases with your family, you can change the account that you use for purchase sharing.
Change the Apple Account that you use for purchase sharing on your iPhone or iPad
You can change the Apple Account that you use to share purchases with your Family Sharing group once every 90 days.
Open the Settings app, then tap Family.
Tap your name.
Tap Apple Account.
In the note under your Apple Account, tap Share using secondary Apple Account.
Enter the email address or phone number and password that you use for your Apple Account.
Tap Use this Apple Account.
Change the Apple Account that you use for purchase sharing on your Mac
You can change the Apple Account that you use to share with your Family Sharing group once every 90 days.
In macOS Ventura or later
Choose Apple menu > System Settings.
Click Family, then click your name.
In the note under your Apple Account, click Share using secondary Apple Account.
Enter the email address or phone number and password that you use for your Apple Account.
Click Use Different Apple Account, the follow the onscreen instructions.
What happens when you change the Apple Account that you use to share media purchases and subscriptions
After you change the Apple Account that you use for Family Sharing, your family members can access or download purchases from that account. However, they'll no longer be able to access purchases or subscriptions from your previous account. This includes DRM-protected music, movies, TV shows, books, apps, or in-app purchases that they downloaded from your previous account, as well as any media subscriptions tied to that account.