To put an Android device in safe mode, the common and easiest method is as follows:

1. Press and hold the power button until the power options menu appears.
2. Tap and hold the "Power Off" option until a prompt to reboot into Safe Mode shows up.
3. Confirm by tapping "OK" to reboot your device into Safe Mode.

In Safe Mode, all third-party apps are temporarily disabled. This helps diagnose if an app is causing problems on the device. To exit Safe Mode, simply restart the device normally. Alternatively, some Android devices allow entering Safe Mode by restarting the device and holding the volume down button as it boots until "Safe Mode" appears on the screen. These methods work for most Android versions 6.0 and above and devices including Samsung, Google Pixel, and others.