In order to "Sign Out" my account from MTDVAT. Follow the steps below instructions: 

Step 1 .  Click the hamburger menu in the top right hand corner of your application.
Step 2.   At the end of the screen, you will see the option "Sign Out".
Step 3.   Click on “Sign Out,” and your device will be logged off from your account.

RoadMap on how to signout my account: Hamburger Menu -> Sign Out -> Continue.