Using canonical tags is essential for SEO as it helps prevent duplicate content issues, which can negatively impact your website's search engine rankings.
When multiple URLs on your website (or external sites) lead to the same or very similar content, search engines might see this as duplicate content. This can dilute your SEO efforts, as search engines may not know which version to index or might divide the value of that content between multiple pages. To resolve this, the rel="canonical" link element is used to specify the "canonical" or "preferred" version of a web page.
<head> section pointing to the preferred URL. For example:<link rel="canonical" href="https://www.example.com/preferred-url" />
If other sites are reproducing your content (with permission) or if you have multiple domains, use canonical tags to point back to the original content on your site. This helps search engines consolidate ranking signals to the original content.