How high the air pressure should be depends on your vehicle and the load. The correct values are usually printed on a sticker found in the door frame on the driver's side and in the manual. If no information can be found anywhere, you can also calculate the appropriate air pressure yourself using a tyre pressure table.
The required air pressure can increase accordingly depending on the load. Never exceed the maximum value by more than 0.3 bar. Otherwise, the centre of the tread will be exposed to greater wear than the sides and driving comfort will be noticeably reduced. The tyre pressure is correct when the tyre rolls with the entire tread in contact with the road. Check the tread pattern from time to time to ensure that it is evenly worn.