This is my first post. I read an article on canonical links and why they are important. My question is: I have set my preferred URL on google webmaster tools. Is it necessary to add the canonical rel tag in my site header?
Welcome to the forums, @Samuel_Whistler. (And apologies for your post getting caught by our anti-Spam plug-in. Sometimes it has off days and picks on innocent posts for no apparent reason. )
If you’re just choosing between example.com and www.example.com then that shouldn’t be necessary. Do you also have a .htaccess redirect in place to direct all requests to your preferred version? If not, I’d advise you to add that.