api integration

2 Things. 1. Create a client portal in my wordpress site. 2. Integrate an api into the client portal. The thought process: A company goes to my site and has the ability to run several reports for free using the api. The key for me is to get them to sign in so I can retain their email address and they can save/download the data from the api. On one page, I would like there to be a button that says "enter domain name" and the api will connect with the third party software and have the data flash on my web page (in a report format). They can then choose to login and save the report or download a pdf version of it. Hopefully this made sense.