Avoid Duplication Of Content
The same website has a different URL like a website called mind stick its URL can be written In many ways :
To show google when you click on the above link then it shows the same page or tells google it is the same website this process is called canonicalization. Canonical Tag is used to preventing the problem of duplication by clicking on a different URL. The canonical tag tells the search engine which type of the result of the URL you want in the search result.
To prevent the duplication of the content we use rel-tag .it is used in the head section of the page in the coded website. Google has a crawl budget we reduce its crawl budget by improving the content of the website. When the crawler sees it has a different URL which URL to index.
Importance Of Canonical Tag
Google does not like duplicate content .when a search engine finds a different URL with content it might slow down your ranking .crawler gets confused about which form of URL to index sometimes it misses some unique content.
Some time search engines get confused about which page be rank for a particular query.
How to implement the canonical tag
Try to use absolute URL
Use lowercase URL
As it is seen that google takes uppercase and lowercase URLs as different URLs so use lowercase URL.
Use self-referential canonical tags