Outside of Educational environments, iPad and iPhone are intended to be single-user devices.
You should each have your own AppleID - used with your own dedicated devices - as using a shared AppleID has implications for privacy and unintentional data sharing. There are many good reasons to keep your digital identities entirely separate:
How to create a new Apple ID – Apple Support
Should you wish to do so, you can continue to share Apps, Services, Purchases and Subscriptions using the Family Sharing features.
Family Sharing - Apple
What is Family Sharing? – Apple Support
Set up Family Sharing – Apple Support
Share App Store, iTunes Store and Apple Books purchases with Family Sharing – Apple Support
Sharing an AppleID between users is a very bad idea. Sooner or later, you’re going to encounter data loss, account lockout or compromise of sensitive data.