A void transaction is to cancel the transfer of funds from the customer's account to your merchant account before the 00:00 auto settlement. But most often this is disabled by default settings. Please seek your service provider or acquirer support for more details.
Void a payment
On launcher, press History.
Select the transaction to enter its detail page.
Press Void at the bottom of the page.
Press Confirm on the alert dialogue if you confirm to void.
Enter merchant passcode and press Confirm.
After the process is done, the existing transaction status will change to Void Approved.
Now, you can issue receipt by print, QR code, email or share receipt image file by whatsapp or other conversation app to your customer if needed.