Hi Sankar
MX 84 Supports following VPNs
1. Site to Site [IPSec Tunnel between offices]
2. Client VPN [L2TP Tunnel for roaming users]
Which kind of VPN are your planning to configure.
As @route_map suggested you may follow the documentation / tutorial accordingly.
Regards,
Ajit
AjitsNW@gmail.com
www.ajit.network