I'm trying to add a div that will exist on all pages of the site, but I can't find out how to add html to the body. I've edited the template phtml file (which only contains one section of the body anyways, so don't think that's the correct way to edit), and changes to the phtml file does not take effect anyways.
How do I go about this? I'm trying to just add a single div to the site, containing a popup configured by an existing javascript file. Just not sure how to add code.
Edit: For example when I inspect a page I see line , but no files or column files contain that line.