Hi guy,
I’m new with Mikrotik. Now, interesting on “RB850Gx2” model.
I have question about VPN feature.[see attached figure]
If I used Mikrotik as VPN Server in Thailand.
Then, Client from upcountry ex. Singapore, Taiwan, Qatar establish VPN connection.
All packet (include Internet) carried out to VPN Tunnel [Used internet via Thailand Internet Provider]
Which mode meet my requirement above , PPTP, L2TP, OVPN ?
Thank you and happy new year 2017 Mikrotik Jedi 
Any VPN tunnel will work with that. As pptp support gets thinner and thinner on current client operating systems, I’d suggest L2TP over IPsec which is natively supported on literally any platform - and it’s really easy to implement on both ends.
For having all internet traffic through the VPN tunnel, all you need to do is tick “send all traffic through VPN” (or similar) at the client’s VPN configuration.
I’d suggest not to give out addresses of your local network for road warriors as shown in your diagram (this would need proxy-arp on your local LAN interface and may cause strange behaviour).
Better create a separate pool for this and have the router do the work it’s supposed to.
Then create src-nat/masquerading rules for traffic originating from your VPN network and going out to the internet.
Done.
-Chris