How to restart your Android phone into safe mode
Press and hold your phone’s power button for a few seconds until Android prompts you to turn off your phone—just as you would normally do to power it down. Next, tap and hold Power off for a few seconds until your phone asks you to confirm that you want to enter safe mode. Tap OK, and your phone will restart into safe mode.
Once you’re done with safe mode, go ahead and power down your phone as you normally would by pressing and holding the power button, then turn it back on.