If you are using an 8.5×11” piece of paper, you’ll first need to cut it down to a square size.
With a separate piece of 8.5×11” piece of paper (to use as a pattern), make a “taco fold” by folding one corner of the paper down so the edges of the paper align.
Use the edge of the paper as a guide to cut off the excess tab of the paper.
Unfold the triangle, then use the square pattern to cut a square from your envelope paper.
Position your piece of paper like a diamond, and the card horizontally, centered in the middle of the diamond. Fold the right point of the paper over the right edge of the card and make a crease, then repeat with the left point. Unfold the paper completely.
Now fold the bottom point over the bottom edge of the card and make a crease, repeat with the top then unfold completely.
Using the creases as guidelines, cut out the four small triangles that your folds created along the edges of the paper.
Fold the bottom flap in, then the right and left flaps. You will see the point of the bottom flap showing between the left and right flaps.
With your pencil, make two small dots on the bottom flap, right where the right and left flaps intersect with it.
Unfold the right and left flaps, then cut off the tip of the bottom flap in a straight line between the two dots. Erase the dots if they are still showing.
Fold the right and left flaps in and add a stripe of glue along the bottom edges of both flaps. Fold up the bottom flap and secure it on the glue.
Lastly, let the glue dry, then your handmade envelope is ready to go!