When you only have one OS on your device or system you normally don't see a boot menu, so to get to Safe Mode in 10 you boot to the sign-in screen, then Shift-click Restart -- that takes you to a boot menu, where you have to drill down a couple few levels to restart, then type in a number to select the option you want.

One way around that is to use EasyBCD to add a dummy OS to the boot menu -- with your copy of Windows as the default, if you do nothing it'll take a few seconds longer to start Windows [you set the time interval in EasyBCD]. And if you hit F8 while the menu's visible you get the menus leading to Safe Mode.

For even faster/easier access you can add Safe Mode with Networking as another option on the boot menu. In EasyBCD you'd add a menu entry for the same copy of Windows, name it something else, e.g. Safe Mode w/Network, save it, in the Advanced section or tab set that entry to Safe Mode with Networking, & save it again. Or I came across a web page with instructions on doing the same thing using Windows own command line tools.

winaero[.]com/blog/how-to-add-safe-mode-to-the-boot-menu-in-windows-10-and-windows-8/

techspot[.]com/downloads/3112-easybcd.html

To be safest, Do Back Up 1st.