Electric field intensity and electric flux are operationally defined differently: The electric field intensity is defined as the force on a unit test charge and given by the units V/m. The displacement field (electric flux density) is defined by charge density built up on a test capacitor and given in units of Coulombs per square meter.

Here, electric flux has a domain of direction with respect to the electric field lines and hence it is a vector quantity. So while representing electric flux we should put the arrow, denoting the vector quantity. But electric field intensity is a scalar quantity.