1. Click "Quick Sale".
  2. Enter "Customer mobile number" whom already is a member of "Prepaid wallet".
  3. The right side of the customer mobile number has the "Balance " of the customer's wallet.
  4. Have to select the service and staff.
  5. Make all your "payment mode button" as "0". Now "Payable amount" have the bill amount.
  6. Click "Prepaid payment button". 
  7. "Save" the bill.
  8. If you want to check the balance of the customer's Wallet, then follow step 2 and 3 again.