Connecting sales buttons between websites

Hi we have an online fitness business and currently have a website that we are looking to sell services through. The website is built in Wix. We also have fitness software called PT Distinction (PTD). What we need is someone to be able to initiate a payment through wix to trigger the activation of the sign up in the fitness software. We need the relative emails to customers to be sent by our info email address. Ultimately we are looking for a seamless purchase experience.