The short-term fix might be to use parental authority to tell her to stop using the phone, demand this from a position of authority and punish her if she doesn't. But short-term fixes never work in the long term. They lead to stress, breakdown of communication, lying and other unwanted behaviour.
An active parent would approach this in a more sustainable way. Tell your daughter how much you love her and how important her happiness and success is to you. Tell her that you believe in her and that you know well that she is mature enough to take care of her own affairs, but as a parent, it is your duty to point out that excess screen time will affect her health and take away from other quality time. Role model by reducing your own screen time and try to spend that time with her doing some constructive and engaging activity. For more on long-term parenting interventions, sign up into the Active Parenting community. Also, read Active Parenting.