I forgot my password to my iPad

You will need to restore the device using a computer. The process will erase the device. Later you can restore your data from a recent back-up. Instructions here…

If you forgot the passcode on your iPad, or your iPad is disabled - Apple Support

Your lock screen passcode? See: If you forgot the passcode on your iPad, or your iPad is disabled - Apple Support

Your Apple ID/iCloud password? If you forgot your Apple ID password - Apple Support