On the Settings screen, scroll down to the bottom and select About phone or About tablet. Find the Build number and tap on it seven times.
A Developer options menu will now appear in the Settings screen
System UI Tuner
More fine-grained control of notifications, more control over your status bar and its pull-down menus, etc
1. Pull down the notification shade twice (to expose the Quick Settings menu), then press and hold the cog icon for a few seconds.
It will begin to spin, then a little wrench icon will appear next to it—this is your indicator that the System UI Tuner has been enabled
2. Scroll all the way down to the bottom of the Settings menu. Depending on what version of Android you’re using, “System UI Tuner” will either be the last or next-to-last option in this menu