Hydraulic system is uses the liquid for the work as an energy. The hydraulic machine pressurize the fluid to power an engine. It is used in many fields and have various advantages such as

1. Capable of moving heavier loads

2. Have high forces than electrical and mechanical

3. It maintains constant force even when the speed differs.

4. Its east to use and less cost effective and safe.

It also used in normal day to day life activities such as found in gasoline pump., Used in cars as hydraulic brakes and also in vehicle maintainence.

Hope this helps you out. Good luck