When we ride the bus to school or the grocery store, we all sit in the same seats and go to the same stops as everyone else. But sometimes, people or groups want to ride the bus in a special way that's different from what the bus company offers.
For example, a sports team might want a bus with more room inside for their equipment, while still having plenty of space for everyone to sit. Or a group of friends might want a bus that feels like a party, with cool lights and music playing.
When this happens, they can ask a company that makes customised buses to build them the kind of bus that fits their needs. These companies can change things like the size, shape, and layout of the bus to make it just right for their customers.
Once the customised bus is built, the people who ordered it can ride in style and comfort, knowing that their bus was made just for them.