You can connect the meter’s voltage inputs directly to the phase voltage lines of the power system if the power system’s line-to-line or line-to-neutral voltages do not exceed the meter’s direct connect maximum voltage limits.
The meter's voltage measurement inputs are rated by the manufacturer for up to 400 V L-N / 690 V L-L.

However, the maximum voltage allowed for direct connection may be lower, depending on the local electrical codes and regulations.

If your system voltage is greater than the specified direct connect maximum voltage, you must use VTs (voltage transformers) to step down the voltages.