The MKS unit for energy is the joule (J).
1 J = 1 N m = 1 kg m2/s2
Energy is a scalar, not a vector. It has a magnitude, but no direction.
What is energy?
Energy is the ability to do work. That's one definition, although not particularly satisfying. It's hard to define energy, but we probably know it when we see it.
Energy puts one more tool in the toolbox we use to analyze physical situations. The approach is different than the one we took with forces.
For an object moving from point A to point B, to analyze the motion using forces we need to know everything about the forces being applied to the object at all points between A and B. Using energy we can focus on what the object is doing at points A and B, and, usually, not have to worry about how it gets from one place to the other.