Usually motors have a thrust test table that shows thrust and current draw at various throttle settings. But if you just have one value you can assume this is the max throttle current draw. So at lower thrust, the current draw will be less.
As you change throttle, on brushless motors it's not only the voltage that changes, but rather the timing between each section of the motor (that is why brushless motors have 3 wires).
Also another thing to remember is that the current draw will also change when you use different propeller, as bigger props require more work to get spinning and will have higher current draw.
I have a few articles here on dronetrest explaining how motors work and how to choose the right motor/ESC/battery for your drone if you want to learn more :-). Or you can ask.ore questions