Hello,
If you used the bank payment option then you can upload the receipt from the booking detail of the user dashboard.
After you complete the payment just go to the user dashboard > Booking and to the individual booking. There you will find the button at the right to upload the receipt. After the receipt is uploaded, the payment status will be updated in the booking of dashboard.
For more clear information you can follow the steps mentioned in the documentation.
https://wptravel.io/documentations/user-documentation/#doc-bank-deposite-75
Regarding the PayFast query, it works separately. You can pay the amount using the PayFast payment gateway.
Hope this helps.
If you have any confusion further then kindly let us know.
Thank you.