To move any existing sales receipt to trash, follow the below steps:

1. Click on Sales Receipt
2. Click on any of the existing sales receipts that you wish to delete
3. Click on the three dots on the top of the screen
4. Find the option to move the sales receipt to the trash
5. Click on the trash icon to delete the sales receipt 

6. You will find a warning that needs to be confirmed for moving the sales receipt to the trash.