It is recommended to change the oil when "engine oil change" message or oil change indicator light is displayed (illuminated) on the central control panel. 

Regarding service intervals: Under normal operating conditions, the recommended maintenance interval is 15,000km or 1 year. If your car is used under extreme conditions outlined in the instruction manual, such as: in dusty environment conditions, police cars, taxis, etc., maintenance interval should be shorter compared to operating under normal conditions. 

Detailed maintenance schedule is provided in VinFast Fadil car manual.