While don't currently support the option for a customer to chose either an immediate payment or a delayed order/quote via the one form, you can achieve this with a flow that involves three forms. You will need a Pro or Agency account to achieve this.
This may actually be beneficial to you in some ways, as all of the manual/bank-transfer payments will then all be listed on the same form's results, making it easier for you to distinguish who has or hasn't paid. Here's how it's done:
- Create an initial form that simply asks what payment method they would prefer to use.
- Then make two versions of the payment/product form, setting up one to take direct payment with Stripe, Braintree, or PayPal Business, and the other to be in "no payment" mode.
- Then go back to the first form's "After Submission" > "Dynamic Success Pages" and then create a page with a conditional redirect for the two payment/product forms: one that directs to the immediate payment form if they select that option, and the other which directs to the non-payment / manual payment form.
- You may also like to send all/some of the data from the three forms to the one Google Sheet using Zapier. That way you can have all the data in one place.