Unable to change payment gateway

Payment gateway is only allowing PayPal. Would like to have this form accept debit/credit card payment. Please help as soon as possible, thank you! 

You can go for PayPal Pro that has an option to pay via Credit Card but you should have a PayPal business account for that.

https://www.jotform.com/help/458-How-to-Integrate-Form-with-Paypal-Pro

Also, please check this guide for the difference between PayPal Pro and PayPal account:

https://www.jotform.com/help/183-Difference-Between-PayPal-and-PayPal-Pro

In order to replace the PayPal payment with another payment processor you would have to delete it and re-add the other payment gateways.

Thanks.