Windows 10 doesn’t offer F8 Advanced Menu by default. The reason people quote for this is better boot times. However, sometimes it is very important for me to enable F8 menu in Windows 10 as I wanted to install some unsigned drivers. You also need this advanced menu to boot into Safe Mood in Windows 10.
Video: How to Enable F8 Menu in Windows 10
Text guide to Enable F8 Menu in Windows 10
To enable F8 menu in Windows 10, first start the Command prompt as Administrator. You can simply type “command” in search and then “Run as Administrator” by pointing at icon. If you get a UAC prompt then press YES.

Now, just enter the below command and press enter. You can simply copy-paste it,
bcdedit /set {default} bootmenupolicy legacy
You will something like this,

Now, you can simply reboot and you can boot into Windows Advanced Boot Menu by pressing F8.
If you at later time, decide that you want to disable this feature then just fire up the command prompt again as administrator and issue this command,
bcdedit /set {default} bootmenupolicy standard
And it will be deactivated with this response,

Enjoy.