You’ll Need:
an ordinary envelope
pretty papers
glue stick
a pencil

Step 1:
Open up your envelope (you’ll use it as a template).

Step 2:
Trace the envelope onto your sheet of pretty paper.
Cut around your template (you will be left with a replica shape of your original envelope).

Step 3:
Fold each side from corner to corner. It should start to resemble an envelope now!

Step 4:
Glue the bottom flap over the two side flaps.  Leave the top flap free.