What you need to obtain a gun license varies with the gun laws in each state, with the kind of gun you want to purchase, and with the person from whom you wish to purchase the gun. Most states do not require a permit to purchase a handgun. Some states require a permit to carry a machine gun or "assault weapon."
Apply in Person
Most states require a permit for concealed weapons. The states that require permits in some situations for firearms purchases include Connecticut, Hawaii, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Jersey, New York, and North Carolina. Some of these permits come in the form of "transfer certificates." For a comprehensive listing of gun laws from state to state, visit http://www.statemaster.com/graph/gov_gun_law_per-government-gun-laws-permits. Most states that require gun permits require prospective gun owners to appear in person to the police department in the city where they live. If there is no local police department, they must apply to the sheriff's office, county magistrate, or local clerk of court.
All states requiring gun permits for purchase require a valid form of identification--either a driver's license or other form of current identification, which carries your current address, your picture, and your birthdate. In most states you must be at least 18 years of age to apply for a gun permit or purchase a gun. A federal law requires those who buy guns from registered dealers to be at least 21 years old.
You must prepare to file information on prior arrests or convictions. Rules vary by state, but most do not issue permits to convicted felons or to those convicted of violent crimes such as assault, aggravated robbery, rape, or murder. In some states a 5- or 10-year time limit is recognized for disqualifying prior arrests.
An array of other factors may lead to restrictions, including commitment to a treatment facility, a record of unlawful possession or sale of controlled substances, a record of domestic violence, being the subject of outstanding arrest warrants or a restraining order and dishonorable discharge from the armed forces. One or more of these conditions may bar you from obtaining a gun permit. Most states also require you to be a citizen or legal alien.
You will have to submit to a background check, which usually takes several days. You may also have to take a firearms safety and training course, and present a certificate of completion of this course to the issuing authority.