If you want to be able to track your package, have someone sign a confirmation that they received it, you can send it thru Xpresspost using the courier address. Canadapost will give you a tracking number that you may check thru their website. When the package is delivered, you will find a scan of the signature there as well.
If you only want to track your package and do not require someone to sign it when received, you may send thru Xpresspost using the PO Box address. Again, you will be given a tracking number.
If you don't want to track your package and do not require signature, send it thru regular mail and use the PO Box address.
If this is not clear enough, let us know