Can you have separate iCloud accounts on multiple Apple devices?

A new AppleID can be created when initially setting-up a new device - or manually when needed:

How to create a new Apple ID – Apple Support

Assuming that you each have devices of your own and have separate AppleIDs, you might wish to consider using Apple's Family Sharing features - allowing you to selectively share purchased Apps, subscriptions and Apple services with the new AppleID:

Family Sharing - Apple

Set up Family Sharing – Apple Support

Share App Store, iTunes Store and Apple Books purchases with Family Sharing – Apple Support

https://www.imore.com/how-set-up-family-sharing-iphone-ipad

Outside of centrally managed Educational establishments or Business/Enterprise environments, where multiple user accounts are supported, an iPad is essentially a single-user device. As such, the majority of iPads do not support multiple user accounts as you might be accustomed with other computers - such as Windows PC and Mac.

Each User should have their own AppleID account - this being used with their own devices. Attempting to use a single AppleID with multiple Users will encounter all kinds of issues, including unintended merging of data.

Be aware that if you sign-out from one AppleID and sign-in with another, unless you take extreme care to not keep a local copy of iCloud data when you sign-out, the locally stored data will be irreversibly merged with the iCloud data of the next AppleID that is used to sign-in.

Once merged, the only method to delete unwanted data is to manually identify and delete unwanted data from the account.