Hey, how do I download it?
This is a warmer, and there is nothing to download. It's just an idea for your lesson, not a worksheet.
Purchase a postcard for each member of your class, writing his or her name in the name and address space.
Turn them picture side up on a table, have each student choose one (without looking at the name), then he or she will write a message to the person whose name is on the other side. If a student chooses the postcard that has his or her own name on it, the student must choose again.