SEO or search engine optimization refers to activities performed to improve a website's rankings in search engines. On-page SEO involves optimizing individual web pages, while off-page SEO refers to activities outside a website like link building and social media marketing. Important on-page SEO elements include optimized titles, descriptions and URLs, as well as quality content, internal links, and image optimization. Proper use of meta tags, HTML structure, and keywords can also boost search visibility. Regularly submitting sitemaps and URLs to search engines helps them discover and index website content.