If you send it to the Robert Speck Parkway address (that is, send it commerical courier), you'll be able to get a signature when they deliver it. That's why the municipal address is there - because the couriers don't deliver to P.O. box addresses.
If you want to mail it to the P.O. box address, I suggest you do Priority Mail and thus use the tracking number on your receipt to log into Canada Post's tracking service on its site to verify it was delivered.
CPCM doesn't confirm receipt of applications. You hear from them once they approve the sponsorship portion of your application, which right now is running over two months, unforch

:
http://www.cic.gc.ca/english/information/times/perm-fc.aspI'm "Finally" ready to send off our application.
I'm headed to a Post Office Branch to send it away. I just need advice on how to send it.
I don't know if regular mail is the right way to go or is there a way to send it where the postman collects a signature to confirm it arrived.
As you all can understand I'm worried if the package were to get lost, although I have back ups, all my original forms and everything would be lost.....pretty much a disaster! haha
I noticed on the website there are 2 addresses...
http://www.cic.gc.ca/english/information/offices/canada/mississauga.asp1 on the top for Common Law Spouse (which we're applying for)
and 1 at the bottom for courier.
I'm a bit confused as to which one is the better route to go.
Thanks everyone!