SP newbie here. Just wanna ask if I can add Sharepoint tags in the HTML master page (.html file). I am quite confused on where should I put my codes. Most articles I found on the web say I should edit the master page. Is it referring to the .html file or the .master file?

Also, is it better (or not) if I break the association of the .html file and the .master file? I think I'll be working on lots of customizations. Should I decide to break it and work directly with the .master file, can I delete the .html file?