How can i sign in to itunes using a new account

Content and Apple IDs -

Content is forever tied to the Apple ID that bought it. Apple does not transfer content from one Apple ID to another. Apple does not merge Apple IDs. You will never be able to access your content bought with one Apple ID with a new Apple ID.

ASC - Late 2012 Mac mini, macOS 10.15.4; Watch, series 5 GPS/cellular, watchOS 6.2; iPad Air 2, ipadOS 13.5; iPhone 8+, iOS 13.5; TV 4th Gen, tvOS 13.4.5;  HomePods, audioOS 13.4.5 and Airport Express w/ Airplay 2

You can try setting up Family Sharing between the IDs if you want to be able to share purchases made with the IDs.

Family Sharing.         

Family Sharing - Set up.       

Correct.