Canonicalization is for normalizing multiple URLs

Canonical tag have more specialty in SEO.  In some website we can find same data content  in the different pages  of the same website or other websites. It makes more confusion to Google bots while catching the webpages and Google bots may consider this as a content duplication problem. So, there's a chance to reduce your site visibility. For avoiding this, we can inform to the Google bots that the data belongs to our site by using the Canonical tag.

As the same way web pages can be loaded in multiple URLs. Here same data will be available in multiple web pages but URL is different. This means the popularity or credits of your webpage will be split to different URLs. Most of the search engines like Google, Firefox and Internet Explorer only gives the credits separately, not in a combined manner. We can also use the canonical tag here for eliminating this problem.

Structure of the canonical tag:  

<link href=https://www.example.com"  rel="canonical"/>

SEO specialists also find another method named redirection to avoiding the problems, which is mentioned above.