What can't you see cash as a payment option while making a sale?
When you are creating an order for the customer who have multiple items in their cart including a subscription plan. For this order, you will only be able to see card as the payment option as it includes a subscription plan for which card payment is mandatory.
In case the customer wants to pay in cash for the other items in the cart then you will have to remove the subscription plan from this order and create a separate order for it.
Once the subscription plan is removed from the order you will be able to see all the payment options