What is SEO? 
SEO stands for Search Engine Optimisation. 
Essentially this is the way people find your website, whether it be through free, organic or sponsored ads. The aim of SEO is to improve your websites ranking (up the page) when people are searching online using a search engine, like Google. 

The better the SEO, the easier people find your website. This can be achieved by paid ads, or keywords given that people are likely to use when searching for you or your business. Keywords can sit within your Google account or within your website. 
For example, if someone is searching "women's leather jacket" and that phrase sits within your website or the keywords you have given google, you are more likely to pop up. 
When you start typing into a search engine you will notice suggestions the search engine gives while they try and "guess" what you are looking up. This is dependant on factors like your age, where you live and what you have searched for before. For example, if I was to search "queen" this week it would give me suggestions such as Queens death, Queen's children, etc as there are a lot of searches currently being done on this and many articles being published online about the subject.