How do I request a payment from a client?

Open the client, go to Payments and choose New payment request from the ⋯ menu. Set the amount, what it's for and when it's due, then Send request. The client gets it in their app and by email, with a card payment button when you take cards.

Each open request carries Remind and Mark paid — use Mark paid when the money arrives outside the app. Packages sold as Not Paid and sessions charged at the end raise their requests themselves.