There are two ways in which you can collect in-person payments.
The first way you can collect is to Manually Type in the Card
1. Open the associated order
2. Add a payment request (shown here: Requesting & Adding Payment)
3. Click "More Actions" > "Public Invoice View"
4. Click the green button in the top left-hand corner
5. Manually enter the card info
The second way you can collect is to Sign up with Square
This allows you to swipe a card in store