How can you make hydrogen gas?

Answer 1

Water (H2O) can be converted to hydrogen gas (H2) and oxygen gas (O2) through the process of electrolysis. In electrolysis, a DC electric current is passed through the water and the two gasses collect at opposite electrodes.

Answer 2

I assume you mean "hydrogen". That's an element - meaning that it's quite difficult to make it from other elements. However, hydrogen is the most abundant element in the Universe (and a fairly abundant element on Earth's crust), so there is really no need to make it. Among other things, you can extract it from water, which consists of about 1/9 hydrogen by mass.