For a postcard you sent to be registered, the receiver must be able to read the Postcard ID. Here are some dos and don'ts for writing the Postcard ID.

• do write it on the left side of the postcard (direction of text is unimportant)
• do write it more than once on the postcard
• do double check that you wrote it correctly

• do not write it under, above or to the right of the address
• do not write it next to the postage area