Powering adafruit motor shield v2

I have Adafruit Motor Shield v2. I'm going to use it for two 6V DC motors. I have problem that I don't what voltage should I put in Motor shield. It has to be 5-12V, but I have 6V motors so should I put 6V power voltage. Here is also link to te motor shield. https://www.adafruit.com/products/1438

It's OK to give it more than 6v. But in that case, you should be careful not to over-drive the motors. Limit yourself to a maximum analogWrite() value which will not overheat the motors. You can test this by checking different power levels (50%, 60% etc) and checking that the motor is not overheating.

Obviously the power supply needs to be able to supply more than the maximum current of both motors. A rectangular 9V battery is not suitable.

hi, can I use a Li-Po battery to give energy at a motor shild v1(adafruit compatible) and 2 stepper motors?

I don't know anything about your experience in electronics so I don't know if you can do it. There are a large number of Li-Po batteries suitable for this but there is an equally large number of unsuitable batteries.