Payment option

Porque voces não agregan mercadopago? é um sistema similar a paypal.

Gostaria que mus clientes me paga-se pelo MercadoPago

To clarify,do you want your form users to pay by check?or do want to have an option for your form users to pay by PayPal or check?

Since you want to add check payment option, there is a  workaround available to achieve your requirement. I would suggest you to please take a look at the following guide which should help you: https://www.jotform.com/help/120-How-to-Set-up-PayPal-Along-with-Other-Payment-Options

Hope this information helps.