This question is incomplete since you did not provide the material about earthquakes that you've been working with. Anyway, I will give you an explanation that will be useful for this lesson.
Explanation:
An earthquake is the sudden movement of the Earth, caused by the sudden release of energy accumulated over a long time. The Earth's crust is made up of a dozen plates approximately 70 km thick, each with different physical and chemical characteristics. These plates ("tectonics") are being accommodated in a process that takes millions of years and has been giving the shape that we know today to the surface of our planet, originating the continents and the geographical reliefs in a process that is far from being completed. Usually these movements are slow and imperceptible, but in some cases these plates collide with each other like gigantic icebergs on an ocean of magma present in the depths of the Earth, preventing their movement. Then one plate begins to move over or under the other causing slow changes in the topography. But if the displacement is difficult, a tension energy begins to accumulate that at some point will be released and one of the plates will move sharply against the other, breaking it and releasing a variable amount of energy that causes the Earthquake.
The areas in which the plates exert this force between them are called faults and are, of course, the points where seismic phenomena are most likely to originate. Only 10% of  earthquakes occur far from the boundaries of these plates.
Subterranean activity caused by an erupting volcano can cause a similar phenomenon.
In general, the term earthquake is associated with seismic movements of considerable dimension, although its etymology strictly means "movement of the Earth".
HYPOCENTRUS (OR FOCUS)
It is the point in the depth of the Earth from which energy is released in an earthquake. When it occurs in the crust of it (up to 70 km deep) it is called superficial. If it occurs between 70 and 300 km it is called intermediate and if it is deeper: deep (remember that the center of the Earth is located about 6,370 km deep).
EPICENTER
It is the point on the Earth's surface directly above the hypocenter, of course where the intensity of the earthquake is greatest.
