A specific state which is defined being a property without the path taken to achieve that state based on it, is understood as a state function.
While the functions whose value is based on the direction taken among two states are named direction or path functions, on the other hand.
The system's thermodynamic condition relates to the current material in temperature, pressure and quantity.
State functions rely only on certain requirements and not on how they have been achieved. State functions for an instance, involve entropy, density, enthalpy and internal energy.
They are known as state functions as they quantitatively define a thermodynamic system's equilibrium condition, regardless of how the system landed in that condition.