Vision: The postman in a dream usually has pleasant information.
A postman bringing money: you are spending money on useless things. Seeing a package: you are about to receive a gift. Writing a postcard: you need to take care of an unpleasant matter.
Receiving a postcard: in a certain situation you are guided more by false hopes than reality. See Package.
Depth Psychology: Mail represents your attitudes, opinions, and thoughts that can influence others. See Letter.
A postcard can also refer to an irritating obligation that should be fulfilled as soon as possible.