Lots of guides and specifications for robotic vacuum cleaners like the Roomba, Xiaomi Roborock, Dyson, etc. talk about the product being "SLAM-based" without offering any explanation as to what that is. Well, SLAM stands for Simultaneous localization and mapping and it is used in robotics to, as the name suggests, construct and update a map of an unknown environment while simultaneously keeping track of an robot's location within it.
In other words, the vacuum cleaner won't simply move around randomly and will instead move systematically. It can also construct a map of the room/house and send that information to an app which you can access on your mobile. This could allow you to place "virtual walls" for rooms/areas that you do not want the vacuum cleaner to enter.
Hope this helps :)