Seems like you have VPS with Ubuntu Server as your default OS. Ubuntu Server comes with CLI (Command line interface) so you won't be getting any UI to operate. You can use SSH Clients and access that VPS via terminal.
But if you still want to Get the UI, then we need to install a Desktop Environment like Gnome, etc.
If you need to install Gnome Desktop environment, you can do the below process and get the UI Display:
First you need to update packages, run the apt command or apt-get command:
sudo apt update && sudo apt upgrade
You can search for desktop package using the apt command or apt-cache command:
apt search ubuntu-desktop
To install the Ubuntu desktop system (gnome 3), run:
sudo apt install ubuntu-desktop
OR use transitional package name for Gnome 3 desktop:
sudo apt install ubuntu-gnome-desktop
IF REQUIRED DIFFERENT DESKTOP ENVIRONMENT
Run the following to install Kubuntu Plasma Desktop/Netbook system (kde):
sudo apt install kubuntu-desktop
Want Lubuntu Desktop environment?, try:
sudo apt install lubuntu-desktop
Execute the following command to install Xubuntu desktop system:
sudo apt install xubuntu-desktop
GDM is a gnome desktop manager that allows to log in into your desktop. Check status with the following systemctl command to verify it is successfully installed:
systemctl status gdm
After this process you can easily use VNC or Remmina or RDP or whatever tool you need to share the Dektop Display.
Thank you
