Is there a machine that blows the hot air into the hot air balloon?

Yes, hot air balloons use a burner, which is a type of machine that blows hot air into the envelope of the balloon. The burner typically runs on propane and produces a flame that heats the air inside the balloon, causing it to rise. As the hot air inside the envelope becomes lighter than the cooler air outside, the balloon ascends. The pilot can control the altitude by adjusting the flame and thus the temperature of the air inside the balloon.