Hey how do i find a Apple user name

If the Apple ID is not yours, then you won't be able to "find" it.

But, if the Apple ID is yours, then

See If you forgot your Apple ID password https://support.apple.com/en-us/HT201487

You also can use Having trouble signing in/iForgot https://iforgot.apple.com/password/verify/appleid to try to recover it.

And you may need to see If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485

Before trying to answer your security questions is very important that you think about your questions, including your birth date, and their answers carefully and try to recall all details you can. If you don't answer them correctly enough, then you easily can lose control of your account.

If you forgot your Apple ID password - Apple Support

Your title asks about user name.

See if you can recover the ID.

Apple ID - How to find your Apple    An iCloud e-mail address is an Apple ID.

Apple ID - Find