If you're thinking about the sheer number of individuals, the majority of animals live in the ocean. This is because the ocean is vast and teeming with life, including microscopic organisms, invertebrates, fish, and marine mammals.
However, if you're thinking about the number of different species, then the majority of animals live on land. This is because terrestrial environments are diverse and offer a wide range of habitats, from forests and grasslands to deserts and mountains.
So, the answer really depends on what you're interested in!