Gather paper, scissors, ruler, and glue or tape
Choose the envelope size you want
Cut the paper into a rectangle
Fold the left and right sides inward to overlap slightly in the center
Fold the bottom edge upward to form the pocket
Glue or tape the side flaps down
Fold the top edge downward to create the envelope flap
Insert the contents into the pocket
Seal the flap with glue, tape, or a sticker