If your app is limited to browsers (so not React Native), you can simply use DOM elements to build a UI 
(that’s including <input>s, and CSS, and all the other nice stuff that come with modern browsers.)
If you’d need just a debugging UI (meaning useful over fancy), you can try dat.ui (it’s used by all three examples.)
If you’re targeting VR, you can also take a look at three-mesh-ui.