I want to know my Apple ID I forgot it

Typically an Apple ID is an email address you have used.

Click on this link to read what to do "If you forgot your Apple ID" --> https://support.apple.com/HT201354

or go directly to this link --> http://iforgot.apple.com/

Also read about "What to do after [or before] you change your Apple ID email address or password" - https://support.apple.com/HT204071

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."

https://support.apple.com/HT204169