1 - Sign on on the till with any staff name.
2 - Find the button named 'Receipt ON / OFF' in the top right corner and press it once.
This button can be also found on Functions page which is accessible on he right column.
You will notice at the bottom of the screen n icon appearing or disappearing, when this icon is present, it means the receipts will print automatically for all sales, it's absence means receipts will not print.