No, window air conditioners (ACs) are designed to cool the air by using a refrigeration system that requires the use of water in the form of condensation. Water is not typically added manually to a window AC unit. Instead, it draws moisture from the air to aid in the cooling process. The moisture is then expelled outside through a drainage system.
If you choose not to use the cooling function and run the AC as a fan only, it will still utilize the existing moisture in the air to help circulate and cool the room. However, it won't provide the same level of cooling as when the air conditioning function is enabled. The fan mode simply circulates the air without cooling it further.