Right now NOAH is a progressive web application that can be accessed at app.noah.com. NOAH will eventually be available for full download in app stores. However in the meantime, you can still add this to your home screen as an app icon!
Chrome:
In your Chrome Browser click on the "3 dots" at the top right of your screen and look for "Add to Home Screen" and click "Add".
Safari:
Click the "Share" button at the bottom of your browser window. It's represented by a square with an up arrow in the foreground. The "Share Sheet" will now appear. Select the option labeled "Add to home screen".