A set of processes used to help search engines find, read and understand the website is called technical SEO. Technical SEO is usually about the background elements of the website. Many processes such as keywords, metadata, indexing are included in technical SEO.
Websites are built using a variety of coding formats and these are usually JavaScript, CSS, HTML. HTML determines the page structure of the website, CSS controls how the page looks, JavaScript controls how that page behaves. The purpose of technical SEO studies is to identify and improve problems that prevent search engines from reading pages correctly.