How do you set up Apple ID when you share an iPad?

Outside of Educational establishments, an iPad is not intended to be a shared device. An AppleID is intended to be used by a single User only. Sharing an AppleID causes multiple issues with maintaining privacy and separation of services.

Whilst it is obviously possible to share a single device, you need to comprehend the implications of doing so - in particular if you also intend to pair the iPad with an iPhone.

If you understand and can articulate your intended usage model, then it may be possible to offer some suggestions as to how the intended outcome may be acheived.