Under the button layout, you can choose the different layout of the virtual buttons.
Setting method
realme UI 3.0 & above versions: Settings > System & update/System/Additional settings > System navigation > Buttons > Button layout
realme UI 2.0: Settings > Convenience tools > Navigation > Virtual buttons > Button layout
realme UI R & Go & S & T & U Edition: Not support changing the layout of virtual buttons, but you can set it by Settings > System > Gestures > System navigation > 3-button navigation.
Related Articles:
How to set virtual or navigation buttons
How to Fix Navigation buttons not working