You can process a sale and generate an invoice / receipt without an appointment. This is perfect for situations when a client drops in to purchase a product but is not there for an appointment.
You can now add products, services and payments to the invoice and print or email it as normal. You can also view this invoice at any time by going to the client's profile and clicking on Invoices (top right of screen) or by going to Sales & Payments >> Invoices.
Invoices not attached to appointments can also be created in the client's invoices list. When viewing the client's invoices if you click "New Invoice" this will create an invoice that is not attached to an appointment.