Hello my friends, here I come to ask you all another question!

I have an old Netbook that is running Lubuntu 16.04 for over a while. Though, I need a fester laptop, and I decided to sell this Netbook on the internet. So, my question here is, is there any way to format Lubuntu from zero, and let the buyer set its password, and everything? Something like when you factory resetting your android phone, and you have to setup everything again, username, passwords, and so on.

Thank you very much, I really appreciate the community support.