How to make a public VPN?

Question

VPN

Tell me how to make and configure a public VPN server under Linux.
Nothing abstruse is required, you just need users to connect to it in the simplest way through a login and password, without installing any certificates and third-party software, that is, using the built-in Windows tools.
I searched the Internet, I didn’t find anything on the road, everywhere I need to install some kind of certificates, etc.

Answer 1

OpenVPN can authorize by password, L2TP in Softether too, smoke mana - there is nothing complicated there.

Answer 2

honeypot what are you doing? :) pptp is broken for a long time and finally.