Operation steps:
realme UI 6.0: Settings > System & updates > Language & region > Region > Change the region.
realme UI 5.0 & 4.0 & 2.0 & 1.0: Settings > Additional settings > Language & region > Region > Change the region.
realme UI 3.0: Settings > System settings > Language and region > Region > Change the region.
realme UI T & R & S & Go & U Edition: Settings > System > Language and input > Region > Change the region.