The 3 pillars of SEO are:

Technical SEO: This includes all technical aspects of a website such as crawlability, indexability, mobile responsiveness, and loading speed, to ensure that the website works well for users and search engines.

Content: This includes all the content on the website, including text, images, videos, and other media. The goal is to create valuable and relevant content that improves the user experience and makes the website relevant for search queries.

Link building: This involves obtaining external links to the website, which increases the authority and trustworthiness of the website. It focuses on obtaining quality links from relevant and trustworthy sources, rather than quantity of links.