I lost my account how can i find that

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 -> 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?