A canonical URL is the one that you would like a search engine to view as authoritative. If an URL is authoritative, it is guaranteed to be the one that customers see when they search for your business or view your site. It solves the issue of multiple URLs for the same site page. For instance, you could www.imrich.com as well as imrich.com and perhaps imrich.come/home.asg. The issue here is that this creates confusion and it means that the search engine might need to select the authoritative link.
In some cases, the search engine might choose incorrectly showing users a link that does not best represent your site. In the past, the URL was used to give users a snapshot of what the site was offering. These days, they can be more creative.
Using a search engine, having multiple versions of the same site can be problematic. This is where the idea of canonization of URLs comes from. With canonization, you choose which URL customer’s reach. For instance, you might have URLs that change based on how the customers reach the page and what path they take. Ultimately, you want to make sure that the URL is the same no matter how they get to that page.
To avoid an issue like this, you need to understand how to use a canonical URL. To do this, you need to let the search engine and your users know which is your preferred URL. You can do that by using the canonical tag. The canonical tag can be added to the URL that you want to be authoritative. Once added, it will ensure that the search engine displays this URL every time rather than any of the other possibilities. The advantage of this is that it removes duplicate content that could be impacting your ranking. But there are other benefits as well.
Essentially, from the perspective of SEO, a canonical tag is like a 301. A 301 ensures that multiple pages are seen as one in the same and users are redirected accordingly. With a canonical URL, this can be accomplished without the need for the redirect. As such, it’s easier for website developers and less noticeable to site users.
When you have multiple versions of the same URL, it creates various issues. Search engines won’t know which version to index, whether to show metrics or which version to rank and they could make the wrong choice. With a Canonical Url, you can avoid this issue and ensure that you don’t lose any traffic.
Canonical URLs will be relevant for a wide variety of different pages on your site, particularly when they can be reached from various sources. If a user is reaching your site from a social network, this could create a Unique URL that will cause duplicate content that you want to avoid. As such, you need to be checking for issues like this on your site and inputting a canonical tag wherever it is relevant.