If a customer would like to pay an invoice in Cash, here is how this can be done in Dash:
Once all of your items are in the cart, press the "Checkout" button. This will take you to the Payment Screen.
The payment type will default to a credit card but if you want to pay by Cash, press the Cash tab.
The amount owed will automatically be entered in the "Cash Received" line. If you enter a smaller amount, then the customer will be "invoiced" for that amount. If they overpay, then they will receive a "credit".
Email Receipt: By default this box is checked. In most cases you will want to send a receipt to your customer but there may be some cases where you choose to not send this.
Split tender: You can add more than one type of payment if you choose. For example a cash and a credit card payment at the same time.
Add Note: A payment note can be added to an invoice for internal records or to pass along any information to the customer.
When finished, press the "Process Checkout" button on the right hand side.