Lock It: Screen Off is a small and efficient app that allows users to quickly lock their Android device's screen without having to click the power button. The app is free to use and is available for Android versions 4.1(Jelly Bean) toLollipop) and Android 6.0(Marshmallow) & above.

Lock It: Screen Off is very easy to use. For Android versions 4.1(Jelly Bean) toLollipop), simply swipe up from the home button to lock the screen quickly. For Android 6.0(Marshmallow) & above, choose the default Assist app and then long-press the home button to lock the screen.

It's worth noting that the app doesn't work on devices with a fingerprint sensor. To uninstall the app, go to Settings -> Security -> Device administrators -> deselect Lock It, then uninstall it in a normal way. If you find the app useful, you can donate to the developer through Lock It: Screen Off - Donate.

Overall, Lock It: Screen Off is an excellent app for those looking for a quick and easy way to lock their Android device's screen without using the power button.