Reset your Apple ID account

Have you forgotten your Apple ID?, Check your Apple ID via your email box, see this Apple article: If you forgot your Apple ID

If you forgot your Apple ID email address or phone number - Apple Support                  

OR see -> Having trouble signing in?

https://iforgot.apple.com/password/verify/appleid

See also -> If you can't connect or sign in to iCloud

If you can't connect or sign in to iCloud - Apple Support

BTW:

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.

What happens when you use the same Apple ID & Password that you use to sign in here?

See also Sign in with your Apple ID -> Sign in with your Apple ID - Apple Support

Contact Apple Support directly, they will help you clear your Apple Account balance, click -> Get Support

Fill in the field >Tell us what's happening<

If you then want to change Country or Region, you must comply with all regulations described here -> Change your Apple ID country or region -> 

Change your Apple ID country or region – Apple Support (UK)