SEO firms are companies that specialize in improving the visibility and ranking of websites in search engine results pages (SERPs). They provide a range of services aimed at optimizing a website's performance in search engines like Google, Bing, and Yahoo. These services are designed to increase organic (non-paid) traffic to a website and ultimately improve its online presence. Here are some common services and activities offered by SEO firms: 

• On-Page Optimization: This involves optimizing various elements on a website, including meta tags, headings, content, and images to make them more search engine-friendly. 
• Off-Page Optimization: SEO firms work on improving a website's backlink profile by acquiring high-quality backlinks from authoritative websites and managing a brand's online reputation. 
• Keyword Research: Identifying relevant keywords and key phrases that potential customers are likely to search for is a fundamental part of SEO. SEO firms conduct research to identify the best keywords to target. 
• Content Creation: SEO firms often provide content creation services, which involve creating high-quality, informative, and engaging content that appeals to both users and search engines.