How do I remove my iPad from my Apple ID because I forgot it?

Did you forget you Apple ID? See if you can recover the ID/password. An iCloud e-mail address is an Apple ID. Use every email address you can think of.

Apple ID - How to find your Apple  -  

Apple ID - Find  -     

Other ways to find your Apple ID

You can check to see if you're signed in to the App Store, FaceTime, or Messages on your iPhone, iPad, iPod touch, or Mac, or check to see if you're signed in to iTunes for Windows on a PC. You can also go to iCloud.com or appleid.apple.com and see if your Apple ID prefills on the sign-in screen.   

If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.

Apple ID - Manage

Apple ID – Forgot Password  *      

Check your Apple ID device list to see where you're signed in - Apple Support

See this link for reference

Go to settings, click on your name and scroll down. Then follow this instructions

1. Tap the device to see its details, then tap Remove from Account.
2. Review the message that appears, then tap again to confirm that you want to remove the device.
3. Want to permanently remove the device from your account page?