A 404 page is what will appear if someone clicks a broken link — which could be from an old blog post or link that's still on Google, or a click action that is not setup properly.
This hinders the UX (User Experience) of your website visitor. In order to counteract that negative experience, we like to make this page fun and interesting. For the Heading, relate it to a problem your business solves. For the Paragraph, let them know what you do and that they are in the right place if that's what they are looking for.
It's also best practice to include a link that takes them back to your homepage.
Note: This 404 page is setup as a site canvas since there is a 404 for both your standard Showit pages and your blog templates. You can edit here, or there, and it will automatically update in both places.