How can I permanently erase data on Internal HDD?
I have a laptop which I use Ubuntu as my primary OS. However I am trying to sell it to help towards a new PC. I want to COMPLETELY erase data on the Internal HDD (Such as passwords, banking info, etc...) and use my Windows 10 USB Installer to put a new Windows setup for whoever it gets passed on to. I do have another PC which I can use to help with this process, if needed.
PS: This is only for an INTERNAL hard drive, not a USB or external hdd.