Download Windows 10 ISO image file from official Microsoft website. Start Rufus and select “Windows To Go” from the “Image option”;
Select your Windows 10 version and press OK;
Uncheck “Prevent windows to go from accessing internal disks” and check-mark the rest options. When done, click OK to continue;
After you are done creating LIVE usb drive for Windows 10, Press F12 for boot menu and select the option in the list to boot from USB flash drive.
Courtesy:
https://www.pcmag.com/how-to/how-to-run-windows-10-from-a-usb-drive
Notes 