Anyone above the age of 12 should acquire a hunting license for them to hunt in Colorado. Hunters older than 18 years are required to buy a Habitat Stamp so they can apply for a license. This applies to 18+ years old non-residents too.
The state of Colorado offers the following types of licenses; resident, non-resident, youth hunting license and military/veteran license.
Either visit an approved license retailer or the Colorado Parks and Wildlife website to apply.