SEO means Search Engine Optimization. As the name clearly states it, the process implies optimizing the technical design, content and configuration of a website to satisfy the requirements of a search engine, usually Google. A relevant and reputable website is likely to be displayed before others in results.
The idea implies making the website, business, product or service findable. However, this aspect also includes optimizing it for the actual people visiting it and not just search engines. The process takes time to comprehend, so it’s better to leave it to a professional consultant.
SEO is a mix of different strategies.