Windows - How to Reset Device

Windows 10 Reset

Click on Windows Start and type 'Reset' in the search box

Choose Reset this PC

Select Reset this PC

Select Remove Everything to wipe clean the device from all existing data.

Watch this video for more help

Windows 10 - How to Reset Windows to Factory Settings 

Windows Reset when Administrator Password is not known

To begin resetting your PC, hold down the Shift key on your keyboard. With the key held down, press the Restart option under your power menu.

This will reboot Windows 10, but rather than loading the operating system as normal, you’ll be presented with the boot options menu. Click the Troubleshoot option to proceed.

More details in this link: How To Factory Reset Windows 10 Without The Admin Password (helpdeskgeek.com)