No, Tailscale is an overlay network. In it's simplest form, it can act as a VPN. But it does much more than that.
Tailscale installs a virtual network device and allocates IP addresses to any device you install it on and sign in with your tailnet. Think of it as a virtual meshed LAN that runs on top of your physical network.
Tailscale becomes your control plane and provides advanced access control options for all your users and devices.