aggiedata said:
Go into Apple ID setting and see Family Sharing. Add the new account. Wife and I did the same.
Wife pretty much has to start from scratch, but you can share stuff too. Like shared photo albums, air dropping contacts, subscribing to each other's playlists, and collaborating on notes. I recommend subscribing to Apple One.
Purchases are shared in Family Sharing, but all accounts tied to a single credit card. You can setup purchasing permissions. Each account has its own iTunes Gift Card Balance.
I keep my parents on my family plan, but I have to keep track and bill them if they buy something. Kinda nice for me because I split the subscriptions we share and bill their half.