Can expats use postal service and what should I know about it?

You can receive it easily if you ask your friend to send to your address (where you are staying or working). I think sending to your working address is best option cause if the postman can't find you, he will give to the receptionist or whoever does the document receiving job.

If you don't have any or can't ask from your friends here, simply go to Post office, ask for a box, give that to your friend. You may need to bring your passport or visa. Note down this and give to staffs in Post office "Tôi muốn có 1 địa chỉ để bạn tôi gửi postcard cho tôi. Tôi không có địa chỉ riêng & muốn có 1 hộp thư để nhận ở đây. Xin hướng dẫn! Cám ơn rất nhiều!

The VN postal delivery is unreliable and irregular, especially to domestic addresses. In fact it is so bad some companies have numbers you can call and ask for a duplicate whatever to be sent.

For Foreigners a good way is to have the postal item sent to POSTE RESTANTE. In TP HCM every quan has a main post office.

So ADDRESSEE (DT:09082427834), BUU CHINH. QUAN 27, TP HCM should, with luck, have the package delivered to the Main Post Office in Quan 27. They will usually call when it arrives (you might want to use a VNese friend's number).

To pick it up you will require ID (passport) and have to pay the fee which would normally be charged for local delivery (don't ask why).

To ensure delivery within VN use 'registered mail' - the more expensive one - as they get a signature. It is actually courier service to such provinces that have courier service.

Thanks you!

Also, should I know my Zip Code or I can use only my full address?

We generally don't use zip codes here, just your full address will suffice.

Even worse in the country, although QN has been a " city " for 25 yrs, there are still many streets without names, ( I can see my house on Google Earth 2003, and my street still has no name ). As Jaitch said, best to have mail sent to your nearest P.O. ( ask for a private mailbox ).
  Last time I received a registered letter, ( sent to my wife's commune's P O ), it took 3 days, just to go the 14kms from the nearest main P O., ( after their 2nd attempt to send it from the UK ).

Talking of addresses, I went to a road in Go Vap years ago looking for a property, the road is a mix of old and new numbers which make no sense at all. After about an hour of trying to figure out the numbering I gave up and went home,as you said in the country it's much worse.

colinoscapee wrote:

Talking of addresses, I went to a road in Go Vap years ago looking for a property, the road is a mix of old and new numbers which make no sense at all.

Some parts of some cities (HCM and Hue) have THREE series of numbers; you have to learn which style is the latest. These, added to Google Maps and Bing Maps, make 5!

colinoscapee wrote:

We generally don't use zip codes here, just your full address will suffice.

Zip codes are spreading. Some of the smaller cities (NHA TRANG) have been completely numbered.

Problem is the VN PO isn't publishing them and don't even use them. But it looks good.

The most confusing street I have found so far was in Tan Binh,Saigon.Found the street no problem, but finding the place I was looking for was a real challenge,even my secretary couldn't find it. The place we were looking for was in another street that went off at a right angle then off at another right angle, but it still retained the address of the original street. Took us over an hour to figure it out.

colinoscapee wrote:

The most confusing street I have found so far was in Tan Binh,Saigon. ...

Check out Dien Bien Phu (HCM)! Cuts through so many phuong/wards and even has several sets of duplicate numbering.