You'll either end up drawing twice the current, give each motor half the driver's current, or give half the voltage to each motor depending on the configuration and the driver.

Wiring in parallel would try to get twice the current drawn through the driver - if it's a constant current driver, then this would effectively split the current to each motor. If your driver is capable of feeding more current, then you could configure your driver to do that.

Wiring in series would end up with the same current, but half the voltage (with everything that entails).