Hi PeterandLorraine,
It's recommended that each unique user have their own Apple ID to keep information separate and ensure delivery to the correct device.
The article How to create a new Apple ID outlines how to create a new Apple ID. Once established, you can sign out of the current Apple ID on one iPhone using these steps:
"Sign out of iCloud and the iTunes & App Store.
- If you're using iOS 10.3 or later, tap Settings > [your name]. Scroll down and tap Sign Out. Enter your Apple ID password and tap Turn Off.
- If you're using iOS 10.2 or earlier, tap Settings > iCloud > Sign Out. Tap Sign Out again, then tap Delete from My [device] and enter your Apple ID password. Then go to Settings > iTunes & App Store > Apple ID > Sign Out."
You may then sign in using the new account. Please note if you use iCloud then you will receive a prompt to keep a copy of the current information or to remove it when signing out. Apps installed under the previous Apple ID should be removed and reinstalled using the new account to ensure access to updates.
If there are purchases or subscriptions you wish to retain access to, you may also set up Family Sharing per Set up Family Sharing.
Regards.