To use an area light, we define a rectangle using the transform tools or the Inspector panel. Area lights emit light from one side of their rectangle. The following screenshot shows what an area light object looks like in the Unity editor:

Area lights are unique from the other types of light as they can only be baked. This means that real-time rendering will not take place during gameplay. The reason for this is to conduct all the processing regarding area lights prior to gameplay. This processing, if accomplished in real time in a game, would likely result in sufficient lag.

As you can see in the following screenshot, the Type is set as Area (baked only) and cannot be changed:

Area lights can be used instead of point lights when baked lighting is okay and you desire software shadows.

To create an area light, we select GameObject | Light | Area Light from the top menu.