Instead of depending on your national and Peru's postal service Serpost, especially when sending and receiving important documents, the standard courier services of course also have offices in Lima. The shipment of letters and parcels from Lima to any other country in the world is easy and trouble free, but expensive. A document to Europe or the US takes around four working days.
Receiving simple document envelopes is also unproblematic. They are normally delivered to your doorstep without delays. But sources reported often unsolvable problems with unjustified and high import taxes and turning up additional fees requested from the various courier services, when receiving mail containing anything else than a document or a piece of paper. So if sending a "care package" to your loved ones to Peru, either be prepared that the receiver has to pay extra duties or delivery charges (even if stated otherwise in your home country) or better send it as certified mail with the normal postal service.