Enable vnc on Kali Linux

No Persistent mode:

apt-get update && upgrade
apt-get install x11vnc
x11vnc -storepasswd

x11vnc -ncache 10 -auth guess -nap -forever -loop -repeat -rfbauth /root/.vnc/passwd -rfbport 5900 -noncache

Persistent mode:

Step:01
Go to the below path cd /usr/local/bin

Step:02
and create the file nano sharex11vnc

Step:3
Enter the following,

#!/bin/sh
x11vnc -ncache 10 -auth guess -repeat -nap -loop -forever -rfbauth ~/.vnc/passwd -desktop "VNC ${USER}@${HOSTNAME}"|grep -Eo "[0-9]{4}">~/.vnc/port.txt

# comment this out if you dont want a pop up telling you which port you’re using

zenity --info --text="Your VNC port is 'cat~/.vnc/port.txt'"

Step:4

chmod 755 /usr/local/bin/sharex11vnc

Step:5

Goto Applications -> Settings -> Sessions and Startup.

Step:6
Select “Application Autostart” and click on “Add” button.
In the Add application, Enter name (Whatever you want), description (can be left empty) and in Command, enter “x11vnc” (without quotes). Click on OK and check the “X11VNC” box and close it.