Illumination flares are typically launched from a flare gun, which is a specialized device specifically designed to shoot flares into the sky. These launchers can be handheld, mounted on vehicles, or even integrated into larger weapon systems.
As for where you can buy one, illumination flares and flare guns are generally restricted items and cannot be purchased by civilians in most countries due to safety concerns. They are primarily manufactured for military and law enforcement use. In some countries, certain types of flares may be available for purchase for specific purposes, such as maritime safety or signaling, but they are usually subject to regulations and permits.
It's important to note that handling and using illumination flares requires specialized training and safety precautions. They produce intense light and can pose a significant fire hazard. Attempting to obtain or use military-grade flares without proper authorization can have legal consequences, and it's strongly advised to only use flares under the supervision and guidance of authorized personnel.