1. Valley fold and Mountain fold

           “Valley Fold” and “ Mountain Fold” are the most important symbols. Every Origami starts out with a Valley and Mountain fold
Dash lines (----------)represent  Valley Fold. Fold either left to right or right to left and you’ve a valley fold.
          Notice that the dash lines  is inside, like a valley.

Here is a Valley fold example.

          For  a Mountain Fold, the crease is at the top and the paper is folded behind itself. Generally a dash-dot (­­­ – . –  .  – . – . – ­. – . – . – . – )represents mountain fold. Here is Mountain Fold Example.

2. Inside-reverse fold and Outside-reverse fold

        This technique will help us fold away the tip of the paper in the proper direction and make Origami more beautiful. Here is the simple furl.

In contrast, this Origami using Inside-reverse fold

3. Squash fold

         Squash fold is a very common fold that use in many Origami. We can make the squash fold everywhere there is a Mountain fold. Let’s see how to make the Squash fold below.

Type1

Type 2

Type3

4. Petal fold

         The petal fold lifts a point and brings it upwards so that the two edges of the point lie together. It is best to prefold both layers of paper along the shown valley and mountain folds before making the petal fold.