I done it years ago when I sold my old laptop with Windows XP.
I made sure none of my personal information, files and partition data stored on laptop hard drive, I used DBAN to wiped data and secured formatted hard drive.
http://www.dban.org/
Then I restored Windows XP from OEM CD, created local account with different name and downloaded all windows update. I downloaded file and data recovery tool as well as partition recovery tool and installed all these tools to checked out if I can recovered files and partition but found nothing to recovered as DBAN did a great job secured formatted my old hard drive so all my old data and previous partition was been completely destroyed. I uninstalled all recovery tools and ran sysprep to removed all my personal information, local account etc, reset it to factory OOBE and shutdown PC then sold laptop.
I suggest you to do same as I did.
Run DBAN from bootable DVDRW or USB stick to secured formatted your hard drive then install Windows 10 with local account, download all updates and also download files, data and partition recovery tools to make sure all your data are secured destroyed, none can be recovered. After that you will neeed to uninstalled all recovery tools you installed.
Then open explorer and navigated to C:\Windows\System32\Sysprep and launch sysprep.exe, make sure system cleanup action set to enter system out of box experience (OOBE), generalize must be ticked and shutdown options set to shutdown. After click OK, sysprep will delete all your personal information, local accounts and settings you entered during Windows 10 installation OOBE and PC will shutdown then you could like to test by boot PC to make sure Windows 10 OOBE worked fine with new buyer by enter personal information and created local account again then reran sysprep again to removed all your details, settings and local account then shutdown so you can sell your PC.