I often want to show a shortcode in a tutorial post without it actually processing the shortcode. For example [contact_form]
In the old classic editor, you could switch to Text and use the html entities
so you could use [contact_form] but alas that no longer works as you can see!
The very simple answer buried away in a 2007 bug tracker and reported here is to use double brackets
If it’s a shortcode with content then you only need the double brackets at the very start and end