There are different kinds of mobile homes. Some are now known as "prefabricated", "manufactured" or "modular" homes; they are built somewhere else and moved to a location. Others continue to be mobile.
Some people prefer a small, compact living space. Others believe that ethically, one should not take too many resources. Still others like to be able to travel and taking their homes works well for them.
For the homes that travel, some also known as trailers are built to be towed behind another vehicle, usually a truck; others are a combined vehicle and home. Those usually tow a car or carry a motorcycle or bicycle. These are also sometimes called caravans.
For the prefabricated homes, they are built in a factory and then moved to a location for placement often on a base and attachment to utilities such as water, electricity and sewage. Often the location is either a mobile home park, designed for such placements or a rural area. These homes used to be limited in width to what could be moved by a truck to the location. But then they began creating doublewide homes. These consist of two halves, each can be moved by a truck and then they are fitted together onsite. They are larger and the proportions are more like other suburban single story homes.