Habitat is the place in which a creature live. A fish habitat is the sea, and a gazelle habitat is a flat desert.
Imagine your home where you were brought up! It has running water, has a range of temperature that is not too high (+50°) or too low (-10°), has certain privacy behind walls that won't show what you're doing, has toilet and waste disposal ways. Let's assume too that you cannot live without a Cinema and a bookshop nearby.
Now imagine you move to another country. You should choose your home where there's a Cinema and bookshop nearby.
This should narrow down your search to fewer places.
This might be a ridiculous example but that area that fits your "life requirements" is what scientists call your "habitat". Scientists will try to recognize what defines it for all living creatures with whatever preferences and scale of the places they like to live in.