Several problems in sending letters from hong kong to the mainland.

1。 Yes, there are generally no six red boxes (fill in the postcode), but it is suggested that the landlord write the postcode of mainland China, and you can write it in the blank space.

2。 The address on the postcard need not be written in traditional Chinese characters, but can be written back in simplified Chinese characters.

3。 All post offices and mailboxes can be sent.

4。 If there is no stamp on the postcard, you should go to the post office to buy it yourself.