Here’s a quick way to make a wave shape in After Effects by essentially just drawing a straight line.

First, create a shape layer with just a stroke by drawing a line across the screen. In the composition, find the shape layer, twirl down and select the Add button. Choose Zig Zag, and adjust the size and ridges per segment to your liking. Then, go back to the Add button and choose Round Corners and adjust the radius as desired. This starts to form the wave shape.

To stylize further, you can choose other options, such as Offset Paths. To draw the wave onto the screen, choose Trim Paths and adjust the end completion percentage as needed. Shape layers offer a lot of options, and as you can see here, you don’t always need to be an artist to create something. 

Hopefully, this gets the creativity flowing. See it in action in the short After Effects video tutorial below: