It sounds like you remember the Apple ID email address but cannot log into the account. You can reset the password with the following link to regain access to the content therein:
Apple ID: Changing your password
- Go to My Apple ID (appleid.apple.com).
- Click “Manage your Apple ID” and sign in.
- If you have two-step verification turned on, you'll be asked to send a verification code to the trusted device associated with your Apple ID. If you're unable to receive messages at your trusted device, follow the guidelines for what to do if you can't sign in with two-step verification.
- Click "Password and Security".
- In the "Choose a new password" section, click Change Password.
- Enter your old password, then enter a new password and confirm the new password. Click Save when done.
The next time you use an Apple feature or service that uses Apple ID, you'll be asked to sign in with your new Apple ID password.
Thank you for using Apple Support Communities.
Thank you for using the Apple Support Community. Due to the nature of your issue you may find more information by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action.