Shortcode

[collapse-pane title=”Heading”]Content[endcollapse-pane] [collapse type=”full” id=”section_id”] [[collapse-pane title=”A light-gray collapsible pane with an apostrophe HTML entity in the heading '” color=”light-gray”] Some interesting content in a light-gray collapsible pane. [endcollapse-pane]]

https://www.wpthemeschecker.com/how-do-i-add-a-collapsible-section-in-wordpress/

https://www.library.illinois.edu/wp-training/shortcodes/collapsible-panes-2/

https://www.bates.edu/wordpress/wordpress-101/shortcode-reference/#the-title-bar