The most useful feature in a POS system is a card reader. There is a list of card readers in the documentation (https://faq.wcpos.com/v/0.5/en/compatible-credit-card-readers.html). To summarize, you'll have to enter the order total into a separate application, such as Payment for Stripe (https://paymentforstripe.com/card-readers), then swipe the card and mark the order as paid. Let's see how to use Stripe.