DDP and Canadian Sales Tax

[always_learning]

Hello, I'm just not getting this so please help me out. 

US seller shipping US to Canada. 

I want to collect the relevant sales tax (GST/HST/PST) at checkout and then ship it DDP and pay the carrier who actually pays the tax authorities. 

Do I need to register with the Canadian tax authority to start collecting this, or am I good as long as the carrier takes care of it?