While any text editor, like NotePad or TextEdit, can be used to create Web pages, they don't necessarily offer a lot of help towards that end. Other options offer more facilities for error checking, syntax coloring and saving some typing by filling things out for you.
Here are a few possibilities for Web editors
Sublime Text - it is quite popular with developers, though there can be a bit of a learning curve to use its many features.
Visual Studio Code - a free open source editor that can run on any operating system. Many developers are already familiar with Visual Studio Code. Many coding videos in this course are demonstrated using Visual Studio Code.
BlueGriffon - a WYSIWYG ("What You See Is What You Get") content editor for the World Wide Web. Powered by Gecko, the rendering engine of Firefox, it's a modern and robust solution to edit Web pages in conformance to the latest Web Standards.
XCode - Mac developers may be familiar with XCode
TextEdit - this is available on Macs, but be sure you're saving as plain text, not as a ".rtf" or ".doc" file.
Notepad - on Windows PC's
Atom - another cross platform editor, created by GitHub. But, beware that Atom and all repositories under Atom will be archived on December 15, 2022!
GitHub itself - check this resource that explains how to create a Web site using GitHub.
Vim or Emacs - great editors, but if you're not already familiar with these, this isn't the time to try.