This origami envelope is one of the easiest to make! Here is a step by step photo tutorial with instructions. You will need some square paper, starting white side up.
start white side up
bring the bottom up to the top
just pinch the edges to make a mark
bring the bottom edge to the center
again pinch the edges to leave a mark on both sides
you can see where the marks should be
fold the bottom edge to the previous 2 marks you made.
fold the newly created bottom edge to the centre marks
there are two marks on either side
bring the top edge down to those two marks.
unfold the previous step and fold the bottom right corner
fold the bottom left corner
turn the model clockwise
fold the bottom edge upwards using the corner folds as a guide
turn model clockwise
again fold up using corner folds as a guide
fold the top corners diagonally aligning to the horizontal fold
now fold the top point down
and tuck it into the bottom fold
finished, if you enjoyed please share this tutorial with your friends!