How does the Catholic Church choose the patron saint of a parish church?

I’m Catholic, and have been since birth. I attend parish of St. Francis in Bakersfield, California. I have noticed recently, that all Catholic Churches, for the most part are named after a Saint, i.e. Saint Francis, Saint Phillip, Saint Anne, Saint Stephen etc. I’ve always wondered, how to they pick which Saint? Is their a list of names to choose from or are they just chosen at random?