SEO visibility means that how your website is looking in Google search results. In other words the presence of your website/blog in Google SERPS for a particular keyword/keyphrase that the user searches for.
There are over 3billion searches happen each day in Google. So it is no wonder to get good quality traffic from Google if you have proper SEO for your website.
There are over 200 ranking factors that affect your website ranking in Google, such as website performance, content quality, engagement, relevance, freshness, etc.
If you feel like you need to improve the SEO visibility of your website in Google you can try consulting an SEO specialist/agency. They can troubleshoot the problems you might not know that is causing your website not ranking in Google.
Hope this helps please comment down below if you have any questions related to SEO visibility.