Android WebView How to put data in Web forms programmatically?

I have to fetch a link from an API and show it to the User via WebView, where user can place an order on third party site, well I have all the information about the user like name, location & address, contact.

I want to put all the data from the variables to a form in this site.

Site: Example link

So when you click on the above link, add couple of items in your cart, and click next on the second page, I want to put the data in the forms.

How can i achieve this?