A canonical tag tells search engines which URL is the main version of a page when similar or duplicate versions exist.
It is written as <link rel="canonical" href="…"> in the page’s head. It helps consolidate signals from URL variations such as tracking parameters, filters or print versions.
Most pages should have a self-referencing canonical. Pointing canonicals to the wrong page can remove pages from search results.
SEO is the work of improving a website so it appears higher in unpaid search results for the searches its customers make.
SEOTechnical SEO makes sure search engines can find, crawl, render and index a website’s pages without problems.
SEOOn-page SEO is optimising the content and HTML of individual pages so they match what searchers are looking for.
SEOOff-page SEO is everything done outside your own website to build its authority, mainly earning links and brand mentions.
