There are a lot of definitions of SEO (spelled Search engine optimisation in the UK, Australia and New Zealand, or search engine optimization in the United States and Canada) but organic SEO in 2020 is still mostly about getting free traffic from Google, the most popular search engine in the world (and almost the only game in town in the UK in 2020):
Before you do anything, and this is key, you need to know what makes your company unique. You need to have a clear concept of the mission of your company. You need to determine exactly what you have to offer because that’s what’s going to make you rank. It’s that simple. SEO is just like regular business. If you’re doing everything on the same or inferior level as your competition, you’re not going to stand out. If you’re not the best result, why should people want to find you? Why should Google rank you? This seems simple, but this factor is often forgotten.
QUOTE: “The purpose of a page is the reason or reasons why the page was created. Every page on the Internet is created for a purpose, or for multiple purposes. Most pages are created to be helpful for users, thus having a beneficial purpose. Some pages are created merely to make money, with little or no effort to help users. Some pages are even created to cause harm to users. The first step in understanding a page is figuring out its purpose.” Google Search Quality Evaluator Guidelines 2019
Advertising with Google won't have any effect on your site's presence in our search results. Google never accepts money to include or rank sites in our search results, and it costs nothing to appear in our organic search results. Free resources such as Search Console, the official Webmaster Central blog, and our discussion forum can provide you with a great deal of information about how to optimize your site for organic search.