editor?

Answer 1

Assuming that you want to know what a HTML editor is ,
a HTML editor is any text editor or other software by which we can create or edit an html file along with js and css.
For more info : https://en.m.wikipedia.org/wiki/HTML_editor

Answer 2

Assuming you want suggestions on which to use this depends on the device you wish to develop on. BRACKETS is generally a good choice for a multiplatform editor.