This article tells you the various ways you can try to discover your forgotten Apple ID --> https://support.apple.com/HT201354 Typically an Apple ID is an email address you have used. If you are currently using a mobile device that is logged into your account, go to Settings and tap your name at the top. Look in Keychain, and in a browser's security settings if you use it to automatically sign into Apple when using a browser.
This article outlines what to do If you forgot your Apple ID password --> https://support.apple.com/HT201487
or go directly to this link --> https://iforgot.apple.com
If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (read this support article: https://support.apple.com/102656#:~:text=If%20you%20can't%20reset%20your%20password,%20request%20account%20recovery ) to regain access to your account. Account recovery might take a few days or longer, depending on the specific account information you can provide to verify your identity. More detail in —> https://discussions.apple.com/thread/255401538?answerId=260044580022#260044580022
If you still need help this page provides country-specific Apple Support contact information ➞ https://support.apple.com/HT201232