My iPad is locked and I don’t know how to fix it.

Locked how? activation locked?

Turn off Activation Lock - Apple Support

If it is locked due to a forgotten passcode, see this.

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

Are you having difficulties with the device Passcode, your AppleID Password, or both?

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

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

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).

You’ll 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:

https://support.apple.com/en-us/HT201354

More information about recovery of your AppleID password:

https://support.apple.com/en-us/HT201487

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