Install VNC Server in Raspberry PI

Setting up your Raspberry Pi

VNC Connect is included with Raspbian but you still have to enable it.

First, run the following commands to make sure you have the latest version of VNC Server and VNC Viewer:

sudo apt-get update 
sudo apt-get install realvnc-vnc-server 
sudo apt-get install realvnc-vnc-viewer

If you’re already using an older version of VNC Server, restart it. If not, and you’re already booted into the PIXEL desktop, select Menu > Preferences > Raspberry Pi Configuration > Interfaces and make sure VNC is set to Enabled.

Alternatively, run the command sudo raspi-config, navigate to Advanced Options > VNC and select Yes.

reff: https://www.realvnc.com/en/connect/docs/raspberry-pi.html