NodeJS server simulate form input and click buttons

This is what I'm hoping to do. I would like to post a form to a node js route and take that data and do the following:

There is another site that has multiple form elements on multiple different pages named follow: step1.aspx, step2.aspx etc. I would like to insert each of my form elements one by one into the other site and press the next button everytime I input another form element so that each page gets one element.

P.S I know it's dumb but I'm trying to get around a web page not having an open api and I'm rather trying to post data directly by simulating a user using node.js. I hope this makes some sort of sense but ask questions so I can be more clear.