Basically, the canonical tag was created to avoid indexing duplicate content by Google. Thus, search engines are able to distinguish the original page from the one generated by duplication. Therefore, they will appear in the search results differently.
Exemplifying the situation, consider that the same content was produced in two different ways to suit different layouts for each platform. In this case, you can choose only one of them as the main one and create a canonical tag redirecting it to the others.
Thus, search engines understand only one of these pages as original, and all traffic generated by the other versions will be reverted in authority to the main URL. It should be noted that the RD Station Marketing tool can easily identify situations involving canonicity.
In other situations, the categorization and the text present in one or more links may be different, with minor changes between them. For example: if a website selling red and green T-shirts has the same URL for both, it is plausible to change the address to www.clothes.com/t-shirts/red and www.clothes.com/t-shirts/green.
Despite being similar, the 301 redirect and the canonical tag have some specific differences, especially when it comes to the exclusion of some URLs. In the first case, a page is taken down and its original link is forwarded to another in order not to interfere with the organic traffic of the site.
On the other hand, canonical links are only identified by Google when two or more addresses are recognized as similar. In this case, more than one URL is allowed, as long as its domain authorities generated when accessed are forwarded to the main page.
All canonical links can be accessed by the user, while in the 301 redirect some pages are not available. Therefore, organic traffic from your domain is not lost, because no URL will be detected as broken.
Using the 301 redirect, no page that no longer exists will appear to users, improving their experience while browsing the site. In this case, this mechanism is able to identify the change made to any URL or even if it was taken down.
When a company undergoes a name change, the old domain of the website also needs to be redirected to the new one. For example: if the URL was previously www.test.com and changed to www.testing.com, the previous address automatically needs to point to the new one.
However, try to keep search engines up to date on any changes made to the domain. Since most of the pages are found by Google, it is essential to apply the 301 redirect to each redirect made.
One of the main mistakes when adopting canonical tags on your website is to see the similarity between many URLs that, because of this, need to avoid duplication. As a result, in addition to Google being deceived about the content of your site, in some situations, there are even punishments in the search results.
In the HTML of a page, the canonical tag must be inscribed in the field to be recognized. Otherwise, it may go unnoticed. In addition, pay attention to the source code and check that all links are correct to redirect the user to the desired URL.