Probably one of my favorite Dramatic Play opportunities of the year in our playhouse is The Valentine Post Office.
I purchased the postman costumes years (and years) ago from Lakeshore. They are adorable, and consist of a jacket, a hat and a mailbag. If you do not have costumes, you can find many templates for postal worker hats online and simply make your own as a headband. Or, do the Post Office without costumes.
Next, fill the playhouse with TONS of writing paper. I have scraps of paper, paper cut as hearts, paper that is ran as cards, and so-on. Then add some markers, pencils, crayons, stamps, or anything else you can think of.
I then give the students one main rule. The post office is for writing letters! You can add pictures to finish your writing, but you must write first!
This is when my independent writing moves to a new level, love it!