Habitat is a place where species get what they need to survive: food, water, cover, and a place to raise young. In other words, a habitat is a plant or animal's home. For people, habitat might stretch from their home (where they have water, cover and a place to raise young), to the supermarket (where they buy food). All the places people go to get what they need to survive can be considered part of their habitat.
Different living things have different needs for food, water and cover, so each kind of animal or plant has a specific kind of habitat.
For example, some sea stars live in rocky tidal pools along the Pacific coast. The rocky tidal zone forms the main part of the sea star's habitat (sea star larvae float through coastal waters, which is also considered part of the animal's habitat).
A moose, on the other hand, has very different needs from a sea star and lives in a very different kind of habitat — like the evergreen forests of Alaska, among other places.