A canonical tag tells search engines which URL a site owner considers the preferred version when substantially similar content can be reached through more than one address.
Canonical tags are hints, not redirects
A visitor can still open the current page. The canonical element is metadata in the HTML head and does not automatically send the browser somewhere else.
Use a complete preferred URL
The TheTecTricks Canonical Tag Generator creates a standard rel="canonical" element from the full URL you provide.
Keep site signals consistent
Canonical tags work best when internal links, sitemaps and redirects also support the intended preferred URL. Avoid pointing unrelated pages to one canonical address.