SEO and SEM are two sides of the same coin, but they consist of very different actions and relate to different aspects of marketing. Seo (Search Engine Optimization) covers the studies that show the correct sites to the user in organic searches of sites that meet Google criteria by scanning the site by search robots. Sem (Search Engine Marketing) is the websites displayed in the advertisement spaces in Google search engines. It covers the work done to get to the first place in advertising areas.
Sites with Seo (Search Engine Optimization) are more suitable for visitors who are more researcher about the website. Sem (Search Engine Marketing) is the website that is shown in the first place above the organic results in search engines. With Sem (Search Engine Marketing), you can show a product or service you want to sell in advertisement areas with the content you want. The important difference between the two is; You pay advertising fees for Sem (Search Engine Marketing). For Seo (Search Engine Optimization), you can show your site in organic searches without paying a fee.