NaOH + H2O → Na+ + OH- + H2O
NaOH is ionic, so it just ionises in water into the Na cation and the OH anion.
But since an acid reacts with water to donate a proton, a base reacts with water to accept a proton. So you can think of it this way - OH- accepts a proton and becomes H2O, and the water, after donating that proton, becomes OH-. This is just a thought.