You’ll need to enable USB Debugging on the Samsung Galaxy S4 if you wish to use developer tools with the device. Enabling it requires a few “secret” steps. Here’s how it’s done.
1. Select Apps > Settings.
2. Tap More… in the upper-right corner.
3. Scroll down and select About phone.
4. Scroll down and tap Build number several times until you see a message that says “Developer mode has been enabled“.
5. Back out of the screen, and now you’ll have the ability to select Developer options.
6. Check the USB debugging selection under Developer options and you’re ready to use your Galaxy S4 with developer tools.