SEO means Search Engine Optimization and is the process used to optimize a website's technical configuration, content relevance and link popularity so its pages can become easily findable, more relevant and popular towards user search queries, and as a consequence, search engines rank them better.
Memos provides SEO optimization for all public memos. All you need to do is set up an instance URL in the System Settings page. Then Memos will generate sitemap.xml and robots.txt files for your instance automatically. You can access these files by visiting https://<your-instance-url>/sitemap.xml and https://<your-instance-url>/robots.txt.