Forgot my password to open my iPad as always use thumb print

There is an Apple article that explains what to do if you have forgotten an iPhone or iPad passcode. Click on the following link: If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support

If that option is not available, you will need to use a computer. See: If you forgot your iPad passcode - Apple Support

Also note that the passcode rather than the fingerprint is required every time after you power an iPad off and back on.

There are certain times when it will ask for a passcode even if you normally use Touch ID or face ID.

Refer to this document for various reset methods you can use to resolve this depending upon what equipment you have: If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support