With the launch of Android 5.0 Lollipop, Google added a convenient Quick Settings panel to the top of the screen, letting you toggle settings such as WiFi, Bluetooth, auto-rotation and more. With the help of a third-party utility, you can add any shortcut you'd like to this slide-down drawer.
The app in question is Custom Quick Settings and it works with Android 5.0 and Android 6.0 devices (if you're on the older version of the OS, you have to root your phone or tablet first). For a couple of dollars you can upgrade to a Pro version that gives you extra features (more on that later).
Before you can get started, you need to enable System UI Tuner, give Custom Quick Settings advanced permissions, and set up a blank tile. Step-by-step instructions for all of these procedures are included in the app, so you shouldn't run into any problems. With that done, it's time to define a new tile.
Tiles have a title, icon, click action, and long-click action. You can toggle switches, open URLs, and launch apps as required. Pro users get a few other launch actions to play around with too. If you pay for the Pro version, you can also access custom icons and icon packs. But otherwise, you're stuck with built-in icons (of which there are many) and app icons.
Remember you can use System UI Tuner in the main Settings app to rearrange tiles and delete them completely from the drawer. Just tap Quick Settings to access the relevant screen. If there are some built-in toggle switches you never use, like Cast or Hotspot, you can get rid of them here.
If you want to make the Quick Settings pane tailored to your exact needs, then it's worth taking a look at Custom Quick Settings. It doesn't interfere with the rest of the OS, and we didn't notice any battery drain while using it. There's also support for Tasker intents for even more possibilities, but again this is only available if you upgrade to the Pro version.