Read this article about removing Activation Lock --> How to remove Activation Lock - Apple Support Unless you have the account information that set the lock or the original receipt from Apple or an Apple approved vendor, you cannot remove the lock.
You will need both the Apple ID and the password.
Typically an Apple ID is an email address you have used. If you are currently using a mobile device that is logged into your account, go to Settings and tap your name at the top.
Look in Keychain, and in a browser's security settings if you use it to automatically sign into Apple when using a browser.
This support article describes ways to find your Apple ID --> If you forgot your Apple Account primary email address or phone number - Apple Support
or go directly to this link --> https://iforgot.apple.com/appleid
If you still need help:
Contact Apple for help with Apple ID account security "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues."
Contact Apple for support and service - Apple Support