What is a Model? When is modeling used?

This is a schematic representation of a real object or process using a picture or a description of the algorithm of its action.
Such an algorithm or drawing will always be a little simpler than a real object or process.
The model can be used when we need to predict the behavior of some object.
A drawing of a person, for example, is also a kind of model, because in the drawing we transfer only the main parts.
The model is also used in programming, in classes.