This happens when a payment method is added to the Sales Order. If you don´t want to receive a customer deposit on the sales order, the transaction should not have any payment method.
A Cash Sale refers to a situation where a Sales Order (SO) is set up with a payment method, indicating that the customer is expected to make an immediate payment upon order fulfillment. It's a transactional state that affects the billing process of the SO.
How can I avoid the 'Cash Sale' mode for my Sales Orders?
To avoid the 'Cash Sale' mode for your Sales Orders, simply refrain from adding a payment method to the transaction. If you don't want to receive a customer deposit on the SO, ensure that no payment method is associated with it.