Kind of a vague question. Kind of like asking what mobile app will connect to your new car.
NAS drives have all kinds of makes and models and manufacturers. You need to use the apps which the manufacturer supports. If it is a NAS setup that can run software on it, then you should look at that software suite to find out what it runs.
Why do you need to connect your phone? Are you hoping to store and retrieve files? To manage the NAS? To do something else?