I use Atom for coding emails. I was having a weird problem with Dreamweaver (the licensed software my team uses) for which the program would lag, despite having the same machine as other members... so I picked Atom, which I knew was freely available and I had used in a previous job.
Atom works flawlessly, it's super lightweight, and has wonderful themes that are really pleasing to the eye compared to Dreamweaver or Visual Studio Code