how to transfer data to new iphone different apple id

Not a feature of iOS. Apps/media/downloads are forever

tied to the AppleID used to acquire them.

Information such as contacts would have to exported from

AppleID1 and then imported to AppleID2.

Documents would have to be moved/located to a neutral

storage that both AppleIDs could access - one to copy into

the storage and the new ID to copy out.

Family Sharing may provide some of what you seek:

Family Sharing - Apple