This is applicable only to KVM based VPSes on CrownPanel -- Also, you can always setup a VNC server inside your VPS and/or enable RDP (if using Windows) as needed.
Login to CrownPanel at the following URL: https://crownpanel.com
Click on the "Manage" button beside the VPS you wish to manage
Switch to the VNC tab and click on the "Launch VNC" button to launch a browser based VNC session or if you wish to use a desktop based VNC client, click on the "View VNC Details" button
To disable VNC you can see the following guide, Disabling VNC on CrownPanel