There is absolutely no industry standard tool or software for UX Design. Designers use a variety of tools to design. Every design/client brief starts with a good old pen and paper sketching and brainstorming. So there is your first tool. After that, it all depends from designer to designer. Some of them use Moqups, Axure, Balsamiq, UXPin, Marvel, InVision and many other tools to build initial wireframes and prototype designs. They later build the final UI either using Adobe Photoshop, Sketch App or Adobe XD.
There are quite a few new tools alsnando launching in the future, so as you can see, there is no dearth to the number of tools available for design. And there is no industry standard too. Just use the tool you find most comfortable to use and that should do it