To use a shortcode, you just paste it into any WordPress page or post. Instead of pasting it, you can type it. (If you use Gutenberg, see below.)
For example, to use the birth report shortcode on a WordPress post, type the shortcode into the editor:
Visitors to your site will not see the actual shortcode. Instead, they will see something that replaces the shortcode. For example, when you use that shortcode on a page, your visitors well see the birth report form. Every shortcode does something different.
You can also add other stuff on the page, either before or after the shortcode. Here is an example that has some introductory text first, and then the shortcode.
How To Use a Shortcode in Gutenberg, The New WordPress Editor
If you’re using Gutenberg (the new WordPress editor), you will use shortcodes a little differently than before. Instead of just pasting or typing the shortcode, the Gutenberg WordPress editor requires 3 steps: