How to add VPN?

A Virtual Private Network (VPN) enables you to send and receive data across   shared or public networks. A VPN encrypts the connection between the device and the internet and it can increases the functionality, security, and manage   ment of the private network.
Note
You need to set a screen lock to save your VPN settings. 

1. Go to Settings > Connection & sharing > VPN.
2. Tap Add VPN at the bottom of the screen.
3. Enter the corresponding information such as Name , Type , Server address , IPSec identifier , IPSec CA certificate , IPSec server certificate , Username , and Password of the VPN.
4. Tap  to save the VPN.