The concept that government's powers come from the people is called

There are multiple different ways this could be answered. It could be said that this is popular sovereignty, which is people vote and whoever gets the most has the power. It can also be called consent of the governed, which means that the people voted and they have given consent to this government to have power. It can also be called a Democracy, which is a type of government where the people choose their leaders.

The concept that government gets its authority from the people and that ultimate political power remains with the people is known as popular sovereignty.