SEO stands for search engine optimisation. It is the process of increasing your website’s visibility in organic (or “natural”) searches on a search engine site like Google or Bing.
Many factors go into how well you rank, including but not limited to: load speed, backlinks from other websites, and keywords used throughout your content on all pages of your site.
You don’t need any previous experience with SEO to do this yourself- just some time and patience as you work through each step! Read tutorials online if you’re interested in learning more about SEO for beginners.