How do you set up monthly payment

Do you mean to ask how to setup monthly payment in a form you want to create?

You can change the Payment type option in the Payment wizard to Sell Subscriptions. Here's how:

1. Open your form and select the payment field then click the Wand icon (payment wizard).

2. Change the Payment Type to Sell Subscriptions. 

Here's a guide: https://www.jotform.com/help/166-How-to-Setup-a-Recurring-Payment-Option

Hope that helps. Let us know if you need further assistance.