Click Start > Settings (or press Windows key + i) > click Update & security
Click Recovery then click Get Started under Reset this PC
Reset offers two types of clean installs:
Just remove my files - this option is quicker and recommended if you just want a fresh start and you plan to keep the computer.
Remove files and clean the drive - if you plan to giveaway or resell your computer, this option ensures the computer is cleaned properly. Its takes a bit longer, but it is recommended if you plan to no longer use this computer.
Click Reset to begin
Windows 10 will restart
Preparing to perform a reset
Resetting - this might take some time depending on the amount of data
Windows will check the drive for errors and fix them.
Windows 10 performs a clean install again
Learn more about preparing your computer for give away or donation: