"switching voltage" has a different meaning than the one you are using. It usually means the voltage that can be switched by the contacts with no damage. Which, for DC and for the "standard" relay, is 30 volts and 5 amps.
You seem to be asking for the coil ratings. Further down on the datasheet, apparently this relay can be ordered with various types of coils. The DC12V part on the part number indicates that the coil requires 12 volts DC to operate. And at 12 volts nominal, the pickup voltage (voltage required to close the contacts) is 8.4 volts and the dropout voltage is 1.2 volts, ie, the voltage that will cause the contacts to open once closed.
But the way it is made to operate is, apply a nominal 12 volts (which could be as low as 10 volts) to the coil and the contacts close. Remove the 12 volts, and they open.
If you are using this to reverse the direction of a motor, you have to verify that the relay is break-before-make, otherwise you will have a momentary short while the relay switches which is disastrous.