Shortcodes are a very powerful feature of WordPress. In essence a shortcode is a placeholder for some other content. A well-known shortcode is the built-in gallery shortcode. Just type
into the WordPress editor and it will be replaced by a gallery of images taken from media uploaded to the post.
The HTML you would need to write to make this happen is pretty hefty; using the shortcode makes it considerably faster. If you need to do any repetitive tasks in the post editor or you need a specific HTML format which takes a while to mark up, you may find that your own shortcode can help.
To find out more about this continue reading here!