Can this H-Bridge circuit be used with 12V?
To use this circuit with a 12V supply R5 &amp; R6 must be rated for at least 0.25W power and the 100 ohm resistors must be rated for at least 2W power. Depending on the transistors used these 4 resistors (100 ohm) may need recalculation to avoid excessive base current and power dissipation. 

However this circuit will not work. One problem is that it produces large cross-conduction currents while switching from one state to the other. When you press SW1, the voltage drops and Q3 starts to turn on a long time before Q1 is completely turned off. In this moment, which may be from microseconds to a couple of milliseconds depending on the transistors used, both transistors are turned on and the current flows from Vcc to GND. To partialy avoid this, you may add a small electrolytic capacitor in parallel with each 100 ohm resistor.

The other, much bigger problem is the resistor values. With 100ohm base resistors connected this way and a 1kOhm pullup resistor from SW1 to Vcc when the switch is open both transistors will be turned on for a steady state. The circuit will short its power supply and if it can deliver enough power (like a battery can) may even produce a fire. For the circuit to work properly with this configuration, the pullup resistors should be at most 5-10 ohm, which will lead to very poor efficiency and a lot of power dissipation.

DO NOT USE THIS CIRCUIT!
They claim that it is tested, but it can't be true.