i have two itunes accounts and would like to sync both to one iphone

Put all of the media in one library. See Re: Multiple listing of each song for deduping advice. Sync the iPhone with the combined library. Generally it pays to use a single account at least as far as apps are concerned as managing app updates on your iOS device becomes complicated when multiple accounts are involved. You have to sign out of one account and then sign into the other. Family sharing may work around some of the issues.

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