What is your nationality? I assume that you are not Canadian otherwise I can't imagine why you are asking this question.
If you are not Canadian, you presumably already have a passport. I guess that a passport would be useful as a means of identity while you're travelling around in Canada.
Or are you American and want to drive from Washington through Canada to Alaska?
To drive through Canada you will need a car, a driving license, suitable insurance and a passport - even if you are a US citizen driving through Canada to get to Alaska form the lower 48.