How to insert a wrapping div structure into a page in the WordPress editor?

Question

WordPress

I made a static page of the site in WordPress and I want one photo to turn over, and on the back there would be its description (flipping). I found on the Internet css and html code for this stray. And if it’s clear how to insert css, then it’s absolutely incomprehensible how to make a hierarchy of wrapping divs with classes, given that there are no divs in WordPress. There is some strange markup there:

[bt_section layout="boxed" top_spaced="topSmallSpaced" bottom_spaced="not-spaced" skin="inherit" full_screen="no" vertical_align="inherit" divider="no" back_image=" " back_color="" back_overlay="" back_video="" video_settings="" back_video_mp4="" back_video_ogg="" back_video_webm=""

Answer 1

Well, judging by this "markup" - this is some kind of highly sophisticated (perhaps not in a good sense of the word) template.
Surely there is a visual page editor there (something like WPBakery Page Builder), just above the main editor there should be bright buttons (visual composer or the like)
. .

Answer 2

In WordPress, the editor has the ability to switch to code mode. The icon looks something like this <>.
And what you gave as an example: [bt_section layout="is a shortcode.