Forgot Apple ID my iPhone is locked to

You cannot find it with IMEI.

I suspect you may be encountering this situation:

Apple has two related features, Activation Lock ( Activation Lock for iPhone, iPad, and iPod touch - Apple Support ) and Find My ( iCloud - Find My - Apple ), which are designed to prevent anyone else from using an iPhone, iPad, or iPod touch if it's ever lost or stolen. Deactivation of either requires knowing the Apple ID and password that set the feature, or by placing a special request to Apple to reset the device. This Apple ID information essentially defines the current ownership of the device.

Click on this link to learn how to remove Activation Lock --> How to remove Activation Lock - Apple Support

or this one for disabling Find My if activation lock has not yet engaged --> Turn off Find My on your iPhone or other devices - Apple Support

If you do not know the required information and you are not the owner, get the owner of the account to remove the lock (the section: "If you no longer have your iPhone or iPad" in: What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support ), or return the device for a refund, or recycle the device. The device is otherwise useless to you. If the owner is unknown and has not provided contact information as a message showing in the login screen, there is no way to contact the owner unless the person who gave you the device knows them.

hello amukss,

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

Click on this link to read about ways to find your Apple ID --> If you forgot your Apple ID email address or phone number - Apple Support

or go directly to this link --> https://iforgot.apple.com/password/verify/appleid#

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."

Contact Apple for help with Apple ID account security - Apple Support