Js and htm file

Hello!

I have a question many people had asked before but mine is different.
I have an .htm file which inside includes javascript.

1. I didn’t find a suitable plugin to run it, most of them is for header,footer or all the pages.
I just need the file to run only on selected pages on page content.

2.I ve also added the .htm file on the server through an ftp program but don’t know what code to add to call it and run properly. The codes i ve added dont work.

Thank you.