Use everyday activities as opportunities to teach about how the post office works. For example, next time you order something online, ask your child how the package will get from the store to your house. Order a small prize or toy and let your children experience the thrill of seeing that process in action and getting something in the mail.
Wait outside at mail time and introduce your child to your postal worker. Talk with her for a brief moment about what she does on her job and let your child watch her place mail in the mailbox. Then let your child retrieve the mail. Point out what the mail truck or mail bag looks like and what uniforms postal workers wear.
Take your child to the post office and ask if he can see behind the scenes. Show him where the mail trucks park, where the letters and packages go in and out and how postal workers sort mail.
Make a mailbox for your child out of a shoe box or empty storage container. Decorate it and talk about what mailboxes are used for. Place envelopes with notes and treats in the mailbox several times per day. Let your children take turns sending, receiving and delivering mail to understand all steps of the process.
Reinforce the lessons you learned through creative clean up. Pretend your child's toy storage containers are mailboxes and the toys are important packages. Tell your child he is a postal worker and he has the very important job of delivering all the packages to the proper mailbox. Offer a reward to him when all the mail is delivered.