Confused about proceedure for mailing transcripts to Canadian Universities

This might seem like a stupid question but I figured I ask here as I could not really find an answer to my question on google. I want to know how to send official high school transcripts in sealed envelopes that I have via USPS to Canadian University. Do I need to put the transcript envelope in another envelope and send it in an old school fashion with a stamp and the mailing address of the college and my own or is it some other way?