If you have not setup your convenience fee yet, follow the article below first.
Once your convenience fee is setup, you can now apply it to your orders as they are entered instead of it only being applied once a client accesses your payment page.
While entering an order, you'll go to your fees tab:
Once there, you'll now have an "Add Convenience Fee" button :
When the button is pressed, you'll get a confirmation box:
Click "OK" and you'll notice the "Convenience Fee" and "Total Fee" fields have updated.
Be sure to Save or Review/Schedule your order!