I use an HTML/CSS editor which is linked to FTP so I can make changes to the files and be able to undo any mistakes I make (which is something you can’t do with the WordPress editor). I have a mac and use something called Espresso. This program isn’t free, but there are plenty of programs out there that you could use that are free if you’re interested in setting this up.
I use Filezilla for the FTP. You can contact your hosting company to see if they can help you get that setup if you want. They’ll be able to give you the login information that you’d need.