If you are approved, when they are ready to issue the visa they require your passport to stamp the visa counterfoil in it and then you must "land" at a port of entry to Canada. Only then will they isue the PR card which they will only mail to an address in Canada. If you are back in Canada when they are ready to issue the visa you can send your passport to them by courier. Yes, as soon as you are landed as a PR you can go to a Service Canada office to apply for a Social Insurance Number enabling you to work.