When you provide your child with a sheet or two of construction paper, a set of crayons, markers, or paints, and an envelope you get instant, mailable greeting-card art.
If you don't have any construction paper on hand, you can use any kind of stationary or paper. Fold the paper over and let your child go to work.
Let your preschoolers work on decorating the card and you can write in the greeting or slogan later. For slightly older kids, just learning their alphabet or Alef-Bais letters, dictate the spelling of the words for them. Let older kids write out their own cards. Along with their artwork, you can include pressed leaves or flowers. In addition to artwork, you can include a pressed leaf or flower.
However your child creates the cards, the recipients are sure to appreciate the personalized effort and message. After all, it is the thought that counts.