You are sign in here . . . with your Apple ID & Password (?).
Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.
You can’t merge multiple Apple ID accounts.
Or have you forgotten your passcode?
See this Apple article: If you’ve forgotten your iPad passcode
If you’ve forgotten your iPad passcode – Apple Support (UK)
See also -> If you can't connect or sign in to iCloud
If you can't connect or sign in to iCloud - Apple Support