Point to Point Tunneling Protocol (PPTP) was created in 1999 and was the first widely available VPN protocol. It was first designed to tunnel dialup traffic! It uses some of the weakest encryption protocols of any VPN protocol on this list and has plenty of security vulnerabilities.
This post explains VPN protocols and how to choose the right one for the best. VPN Protocols: PPTP VS SSTP VS L2TP/IPSec VS IPSec/IKEv2 VS OpenVPN VS SoftEther VS WireGuard.