Search engines such as Google and Bing use bots to crawl pages on the web, going from site to site, collecting information about those pages and putting them in an index. Think of the index like a giant library where a librarian can pull up a book (or a web page) to help you find exactly what you’re looking for at the time.
SEO is a fundamental part of digital marketing because people conduct trillions of searches every year, often with commercial intent to find information about products and services. Search is often the primary source of digital traffic for brands and complements other marketing channels. Greater visibility and ranking higher in search results than your competition can have a material impact on your bottom line.
However, the search results have been evolving over the past few years to give users more direct answers and information that is more likely to keep users on the results page instead of driving them to other websites.
Also note, features like rich results and Knowledge Panels in the search results can increase visibility and provide users more information about your company directly in the results.
In sum, SEO is the foundation of a holistic marketing ecosystem. When you understand what your website users want, you can then implement that knowledge across your campaigns (paid and organic), across your website, across your social media properties, and more.