The Realme P4 doesn’t have a built-in system-wide dark mode like many newer phones do. There’s no setting to enable a dark theme for the entire operating system. The only way to get a dark mode experience on a Realme P4 would be through individual apps that offer their own dark mode settings.
Check within each app you use. Many popular apps (like social media, email clients, and browsers) have settings to enable a dark theme within their own app preferences. This will only darken the interface of that specific app, not the entire phone.