This is the 7239th most frequent Russian word.
включить
To turn on; to enable.
In this sentence, "включить" means to turn on or activate an electrical appliance or device, represented by the light.
Я должен включить свет в комнате.
I need to turn on the light in the room.
Here, "включать" (as the present tense form of "включить") means to include something as part of a set.
Этот новый смартфон включает множество полезных функций.
This new smartphone includes many useful features.
In this usage, "включить" means to incorporate or add information into a larger context.