There are dozens of effects you can add to artwork in Illustrator, both vector and bitmap types. These are some of the many features we explore in our Illustrator courses. 
Effects can be found in the drop-down menu at the top of the Illustrator interface. First create some artwork, as in the example here. We started by creating a yellow rectangle, a red rectangle, a blue circle and green line. There are two basic types of effects in the drop-down list: Illustrator Effects and Photoshop Effects. The former will give vector appearances, with sharp edges and solid colours; the Photoshop effects are like the filters in Photoshop itself. They will give a more pixel-based, rasterized effect, like adding noise to a shape.
As mentioned, there are dozens of effects, and the best way to explore them is to try them out. Here are a few we tried in class. On the yellow rectangle we applied Effect > Warp > Flag. Then Effect > Stylize > Drop Shadow. On the red rectangle: Effect > Distort & Transform > Zig Zag. Then Effect > Stylize > Scribble. On the blue circle: Effect > 3D > Extrude & Bevel. Then we titled the view cube, adjusted the extrude depth, and changed the Bevel to Classic. On the green line, we added Effect > Stylize > Add Arrowheads > and tried the various options on the start & end points.
Note that when you add an effect, this is listed in the Appearance panel, and can therefore be adjusted at any point by double-clicking in this location.
Whether you’re a complete beginner or self-taught, our courses will help you gain self-confidence in your Illustrator workflow, as well as adding to your professional skill-set. See many examples of our Illustrator clients’ work on our Facebook page.
Other related Illustrator Blog Posts:
Illustrator workspace
Illustrator basics
Illustrator clipping masks
Illustrator live trace
Illustrator brushes