How do I change the paypal account link to my form

i need to change my paypal account link to my form

To change the PayPal account used for your form you need to first edit your form in the Form Builder, scroll down until find the payment field and select it, once selected click on the wand icon and you will get the payment wizard where you can change the PayPal email address info, here is a screen-cast for easy reference: 

I hope this helps.