You can top up your mobile credit through the Boost app by following the steps below:
1) Navigate to the "Prepaid" page
2) Scroll down and click on the "Credit" button
3) You will be directed to the "top up mobile credit" page.
4) Key in your desired top up amount
5) Enter your 6-digit transaction PIN
6) You will be directed to the next page that notifies once the transaction is completed.
7) Shake your mobile for extra cash back
And you're all set! You will receive a message from your mobile operator notifying you of the successful top up!