Forgot the password to my iPad.

If you enter the wrong passcode too many times, you’ll see a message to say that your iPad is disabled. If you can’t remember your passcode, you need to erase your iPad, which deletes your data and settings, including the passcode.

If you backed up your iPad, you can restore your data and settings after restoring your iPad. If you didn’t back up your iPad before you forgot your passcode, you won't be able to save the data on your iPad. Follow the steps below to remove your passcode.

https://support.apple.com/en-au/HT211078

If your iPad is disabled, or you have forgotten your iPad passcode, you’ll need to follow this process:

If you’ve forgotten the passcode on your iPad, or your iPad is disabled – Apple Support

You’ll need access to either a PC (with iTunes installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS).

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

You may also need your AppleID and associated password. If these have also been forgotten, they can be recovered here:

https://iforgot.apple.com

To recover your credentials, you’ll need access to one of the following:

• Your primary email address mailbox that corresponds with your AppleID
• Any of the secondary/recovery email addresses that should be configured for your AppleID account
• Any of the trusted telephone numbers (fixed line or Cellular/Mobile) that are associated with your AppleID

Unless you AppleID account has not been fully/correctly configured, or has been seriously neglected, recovery of the AppleID and password should not be difficult.

More information about recovery of your AppleID:

If you forgot your Apple ID - Apple Support

More information about recovery of your AppleID password:

If you forgot your Apple ID password - Apple Support

When you recover access to your credentials, you would be well advised to log-in to your AppleID account from a web browser - and verify/update any email addresses and trusted telephone numbers:

https://appleid.apple.com

Thanks @Jeffrey for sharing https://support.apple.com/en-au/HT211078/ because it solved my problem in few seconds. Thanks again.