Speedlights are a type of flash that is adjustable both in terms of its brightness and the angle and direction it fires. This makes them fantastically versatile tools for lighting your photos. Speedlights can swivel left and right, and up and down, meaning you can fire your flash in many different directions while still pointing the camera lens towards your subject. This is great for if you want to aim your flash at something other than your subject, such as a reflector or even just a white wall, and reflect the light onto it. Additionally, the brightness of the flash can be adjusted from low power all the way up to full blast.
Allowing further versatility is the fact that speedlights can be used with remote firing devices, where one goes into the hotshoe of your cam, and the other onto the base of the flash. Then you can put the flash wherever you want and it’ll still fire in tandem with the shutter. You can even set it so multiple speedlights are synced with the transmitter on the camera, meaning you can have multi-point lighting using entirely speedlights.
For a demonstration and further explanation, check out the video below!