Each robots.txt file should specify sitemap file locations. Sitemap files contain a list of page URLs that you want indexed and are read by search bots. These files can also include metadata that describes when pages were last updated and how often different pages are updated to help crawlers index your site more intelligently. A sitemap location should be specified in the robots.txt file with a line such as Sitemap: http://example.com/sitemap.xml. A robots.txt file can include more than one sitemap reference. Learn more.
Each page should have a descriptive H1 heading to help search engines and users understand what that page contains. Headings can be added to web pages to give structure to the content in the same way headings are used in books and articles. The most important and highest ranking heading in HTML is called the H1 heading. This is followed down in level of importance by H2, H3, H4, H5 and H6 headings. The H1 heading is like the title heading of an article and similarly should give an accurate and concise description of the entire document to help guide readers. The keywords used in page headings are also treated as a ranking signal by search engines. H1 headings are added to the HTML of a page with an
All pages should specify a valid canonical URL to get more control over how duplicate URLs are treated by search engines. When a set of URLs on your site return duplicate or near duplicate content, search engines will select a single definitive URL for that content called the canonical URL*. This URL will be crawled more often, will take priority in search results over URLs with duplicate content and search rank boosting backlinks to the URLs with duplicate content will be viewed as linking to the canonical URL. Note that *"self-canonicalizing" a page by setting its canonical URL to itself is both valid and useful as it can help eliminate potential duplicates such as when pages may be linked to with tracking URL parameters. To suggest the canonical URL for a page you can 1) add a tag inside the page's tag (most common) or 2) add a Link: <...>; rel="canonical" header to the page's response headers. Google suggest giving absolute canonical URLs over relative ones. Search engines are likely to ignore your canonical URL suggestion if you 1) include multiple canonical URL suggestions per page or 2) suggest a URL that is broken, redirects, isn't indexable or isn't itself canonical. Keep in mind that for exact duplicates you should consider if it is more approriate to use 301 redirects over canonical URLs to consolidate duplicates instead. Learn more.