A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope.
An advertising postcard is a postcard used for advertising purposes (as opposed to tourism and greeting postcards). Because the postcard begins as a blank sheet of paper, the options for what may be advertised are endless. postcard printing are used in advertising as an alternative to or complementary addition to other print advertising such as catalogs, letters, and flyers. Advertising postcards may be mailed or distributed by other means.
I choose these post cards print from amazing web site Behance, i recommend you to visit this site to find a lot of creative ideas of design print.
I hope you get your inspiration.