Taking information from UI page and saving in .txt file

Hi, I've read alot of stuff on how to write information to text files in c# but for the life of me, I don't seem to be able to get information from a menu page on my UI to write to a text file. I have an input field, a dropdown menu and toggle selection. I'm trying to save the information that the user inputs into these fields into a text file under specific headings on the press of a button.

Any help with this would be extremely appreciated!

Thanks in advance