Outside of Educational environments, iPad and iPhone are intended to be single-user devices.
You should each have your own AppleID - 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.
If you are sharing an AppleID, whilst you might consider disabling Keychain to “hide” your passwords - it is trivial to re-enable. You’ll have similar issues with Contacts, Calendars, Reminders, Notes, Messages etc.