Work with HTML documents in TextEdit on Mac

You can use TextEdit to edit or display HTML documents as you’d see them in a browser (images may not appear) or in code-editing mode.

Note: By default, curly quotes and em dashes are substituted for straight quotes and hyphens when editing HTML as formatted text. (Code-editing mode uses straight quotes and hyphens.) To learn how to change this preference, see New Document options.

Edit HTML files

1. Open the HTML file with TextEdit app  on your Mac

2. find sections to be edited using CMD + F.

3. after making changes, don't forget to save it.

or you can find some references on:

https://www.youtube.com/results?search_query=how+to+use+textedit+html+on+mac+