What does this mean?
You may find the following message: "No 'H1' tags (headings) were found on your page"; However these are an important element of any website, as they structure content and text in a meaningful and hierarchical way.
Headings significantly improve the readability of content for visitors of a site. This works similarly with search engines, as they give Google an overview of the page content and the weighting of individual subtopics.
What could you do?
You should add H1's to your website by accessing your content management system and looking for the headers option.
For more information: https://www.webfx.com/internet-marketing/can-H1-improve-SEO.html