Here's a simple HTML test page done using Emacs. For context: C-c RET is for <p> (paragraph) blocks, C-c 1 is for <h1> (header 1) blocks, just in case you forgot, or are new to the ways of the Church of Emacs.
https://files.catbox.moe/0dnrks.html
(save it to your computer, and view it locally, in case.)