Can I merge two Apple ID accounts

No, you can not merger Apple ID accounts at this time. You can, however, sign into one device with different ID accounts. Merging data from one account to another before deleting the unwanted ID account can be done by backing your data up to Icloud or family sharing. With Family sharing you can share the data you want to save to another device and account . Once the account receives the shared items, you can download them to the desired account you wish to make your main.

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Merge apple ID - Apple Community