Do online orders print by themselves on my Android POS, or only on the Windows app?

Both. A POS that sells and can reach a printer looks for new tickets every few seconds, and so does the GetMenu Print app on a Windows PC, so the moment an online or delivery app order reaches the kitchen its tickets print at each station and at the counter. Tick Also print a receipt copy for every online order under Settings → Printing & receipts for a receipt for the bag or the driver, choose 1 or 2 copies, and tick the dine-in line if guests ordering from the table QR should print a receipt too. The POS and the counter tab in the docs covers online orders on paper.