In order to edit your personal details, follow the RoadMap below:
Step 1. Click on the hamburger menu,  in the top right corner of your MTDVAT application.
Step 2. Choose View / Edit my Account.
Step 3. Then, update your email as follows:  update Email -> Continue with E-mail Update  -> Enter Your Account Email (Current) , Your Account Email (New) & Re-type Your Account Email (New) -> continue -> Enter 4 digit passcode for confirmation -> Enter verification code -> Continue.
Finally, your e-mail will be updated.