Native Americans designed many different arrowheads – about 1,200 types are on record – and much can be determined about an arrowhead if you have simple information like the material it's made of, where you found it and its shape and design. When you've properly identified the arrowhead, a world of culture and history will open up to you. Though the object itself was only used by one individual, most likely a man, for hunting and fishing, it is the gateway to a culture that existed possibly thousands of years ago, on the same soil you stood on when you found it.
Consider the Location
Identify the location where the arrowhead was found. If you know the state or region where the arrowhead is from, that will narrow the list of possible projectile points from 1,200 to a couple of hundred options.
Examine the Material
Identify the material the arrowhead is made out of if you don't know the region it came from. Chert, for example, is native to the Illinois and Missouri area.
Look at the Shape
Determine the overall shape of the arrowhead. For example, is it stemmed, stemless or notched? If it's stemmed, note the shape of the stem; stemless, whether it's fluted or not; notched, whether it's notched in the side or from the corner. The location and the design of the arrowhead is enough to narrow the type to only a dozen possibilities.
Do Some Research
Consult a book that specializes in the projectile points from your area to cross-check your arrowhead with already identified ones. "Arrowheads & Stone Artifacts: A Practical Guide for the Surface Collector and Amateur Archaeologist" by C. G. Yeager is a classic. Two other options are "Arrowheads and Projectile Points" by Lar Hothem and "The Official Overstreet Identification and Price Guide to Indian Arrowheads" by Robert M. Overstreet.