help with travel document for canada

I landed canada a few months ago and came back to US. Now I am informed that I need to take pictures for maple card in canada. I heard I may apply for travel document to re-enter canada. Anyboday had this experience in applying for travel document like what kind of documents needed to apply, how long it takes to get it and how it is good for? The document for application need to be origianls or photocopies? Is it possible to apply for it by mail? Which canadian consulate in US I should send application. Does the consulate provide one-day service if I have to go there in person? Your advices and experiences are highly appreciated!