Any American citizen over 18 years of age can obtain a GMRS license from the Federal Communications Commission. The FCC charges a $70 licensing fee, and the license is valid for ten years. No test is required. The license covers all of the licensee’s immediate family members, including spouse, siblings, children, and parents.
PARA maintains several GMRS repeaters which can greatly extend the range of communications possible with GMRS radios. A GMRS license is required to use a GMRS repeater.
Why do I need a GMRS license and how do I get it? (Midland)
FCC GMRS License Information (Buy Two Way Radios)
How to apply for a GMRS license and receive your FCC call sign (RadioReference.com)