Start off with a square piece of paper.It can be any type of paper.
Draw a light line connecting two of the corners and turn the paper like this.
Pull the bottom corner up a little past the line and crease.
Erase the line you drew earlier.
Fold both the left and right corners in and cross them over the bottom corner.If they all don't meet at exactly one point it's okay.
Put glue on the bottom flap and glue both the left and right flaps into position.
Fold the top flap down to finish the envelope.
Make a stamp or buy one and add it on.Don't forget to add the proper information onto the envelope.
Thanks so much for checking out my first guide.If you have questions comment and also let me know how I did.