How to disable passcode and manage Touch ID on iPad 8th gen?

Much of your iPad’s advanced functionality simply won’t work unless a Passcode is set/enabled - such as TouchID/FaceID and Keychain stored passwords.

If you delete the Passcode from your iPad, all security functions will stop working and critical security functions, including TouchID, will be inhibited; your Keychain and all saved Passwords will be deleted from your iPad.

As documented by Apple in its Security Guide, for devices with TouchID or FaceID enabled, you device Passcode is reportedly required in the following circumstances…

A passcode or password is also required if the device is in any of the following states:

• The device has just been turned on or restarted

• The user has logged out of their Mac account (or hasn’t yet logged in).

• The user hasn’t unlocked their device for more than 48 hours.

• The user hasn’t used their passcode or password to unlock their device for 156 hours (six and a half days), and the user hasn’t used a biometric to unlock their device in

4 hours.

• The device has received a remote lock command

• The user exited power off / Emergency SOS by pressing and holding either volume button and the Sleep/Wake button simultaneously for 2 seconds and then pressing Cancel.

• There were five unsuccessful biometric match attempts (though for usability, the device might offer entering a passcode or password instead of using biometrics after a smaller number of failures).

When Face ID with a mask is enabled on an iPhone, it’s available for the next 6.5 hours after one of the following user actions:

• Successful Face ID match attempt (with or without a mask)

• Device passcode validation

• Device unlock with Apple Watch

Any of these actions extends the period by an additional 6.5 hours when performed.

Okay, your clarification is helpful...

Start by trying enrolling a new/different fingerprint:

Settings > TouchID & Passcode > Add a Fingerprint

If you have already enrolled five fingerprints, you will need to delete one or all of them before you can add another.

The iPad User Guide describes the straightforward process of setting-up TouchID:

Set up Touch ID on iPad - Apple Support

If you are having difficulty setting-up TouchID, refer to this support page:

If Touch ID isn't working on your iPhone or iPad - Apple Support

Isn’t that accomplished using this switch?

… or this one?

The iPad is a locked down device and can be only access via a passcode.

Excellent. I'm delighted that the problem has been successfully resolved.