There are several types of postcards you can offer your clients. The most common ones are direct mailers. These are especially useful if your client wants to send information to their clients or prospective clients, directly to their mailbox. I am able to provide you with a design or just help you make sure that they are within postal regulations.
Regular postcards will not have a space for an address but can be handed out to prospective clients so they can know what services your clients offer.
Lastly, there are also rack cards that function the same way as postcards, but are longer in size and normally fit in brochure containers; so more space for information.
Below you will see some examples of all three types.