Swetaa, if you are close to canadian counsulate office than just go there with your h1b approval notice, appointment letter of US consulate from canada ( you will get this online once you take appointment ) and employer letter this is good enough to get canadian visa. but if live far away from canadian consulate than you have mail it with required fee $85 for single entry and $135 for multiple entry. In calgary they give h1b visa in same day. But make sure your name does not match with other people in US. If it match than they will do background chek which may take 3-4 weeks.