To boot Windows 10 in Safe Mode, there are several methods:

1. From the login screen: Hold the Shift key, click the power button, then select Restart. After restart, go to Troubleshoot > Advanced Options > Startup Settings > Restart. Press 4 to enter Safe Mode or 5 for Safe Mode with Networking.
2. Using the System Configuration tool (msconfig): Press Win+R, type msconfig, go to the Boot tab, check Safe boot, then click OK and restart. The system will boot in Safe Mode until you uncheck Safe boot.
3. By interrupting startup: Turn off the PC forcibly 3 times as Windows starts. This triggers the Automatic Repair mode. Then follow Troubleshoot > Advanced Options > Startup Settings > Restart and select Safe Mode option.
4. Enable F8 key legacy method (optional): Use Command Prompt as admin to run bcdedit /set {default} bootmenupolicy legacy to enable F8 key at boot, then press F8 repeatedly during startup to select Safe Mode.

The easiest common approach is to Hold Shift and click Restart, then select Safe Mode from the startup settings menu.