Simple way to draw a shark:

Step 1: First draw a two-line triangle as the upper fin of the shark, and draw two curved lines on both sides of the triangle. The first one on the left is shorter and the one on the right is slightly longer.

Step 2: Draw a downward curve on the left shark’s head until it reaches a position where the upper fins are parallel. Next draw another two-line triangle pointing to the right, slightly smaller than the upper fin.

Step 3: Draw a two-line triangle in the same position pointing to the left. Draw a curved line going up and to the right, but not connecting, leaving room for the tail.

Step 4: The tail part is composed of two two-line triangles. Start drawing a larger two-line triangle at the top and stop at the bottom line. Draw another two-line triangle below to connect the tail, so the shark's body is complete.