Sewing on a button is very simple once you know how to do it! I'll teach you how to sew on both shank and flat buttons so you're covered anytime one falls off. :)
Step 1: Types of buttons.
Flat buttons are the most common kind - they're what you'll find on dress shirts and most clothing. They have two or four holes, depending on the style.
Shank buttons have no holes on top, but they have a small protrusion on the back that is hollow at the end. They're more often found on dresses and coats.