how to restore my email address as Apple ID

Hello Idhelpp,

If you are referring to changing the Apple ID that is signed in to your iPhone, the steps here will guide you through signing out of the current Apple ID to be able to sign in with a different Apple ID: Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support

1. "Go to Settings, then tap your name. 
2. Scroll down to the bottom.

3. Tap Sign Out.

4. Enter your Apple ID password and tap Turn Off. Forgot your Apple ID password? 

5. Turn on the data that you want to keep a copy of on your device.

6. Tap Sign Out.

7. Tap Sign Out again to confirm that you want to sign out of iCloud."

If you merely want to change the email address associated with your current Apple ID, this guide will help: Change your Apple ID - Apple Support

Take care!