What is motivation in psychology?
Motivation can be applied to various types of psychology. For example, in Industrial Organizational psychology, you learn about motivation in the workplace, and how that can be used to the advantage of productivity in a work environment.
At a basic level, there are two types of motivation: intrinsic and extrinsic. Intrinsic motivation is doing something for the pleasure or enjoyment of it. Extrinsic motivation is doing something for a benefit or to avoid consequences. For example (I am sorry if this sounds dumb), if a girl scout person was helping an old man cross the street, there could be different motives for her actions. The intrinsic motivation is that she helped him because she really wanted to help the old man. Contrastingly, she could've just helped him just for the girl scout badge she would receive if she helped him.
This is just very surface level information, as motivation as a topic can get more complex.