1. Allow clients to connect from any host using xhost+
Execute the following command to disable the access control, by which you can allow clients to connect from any host.
$ xhost +
access control disabled, clients can connect from any host
2. Enable X11 forwarding
While doing ssh use the option -X to enable X11 forwarding.
$ ssh username@hostname -X
Enable trusted X11 forwarding, by using the -Y option,
$ ssh username@hostname -Y
3. Open GUI applications in that host
After opening ssh connection to the remote host as explained above, you can open any GUI application which will open it without any issue.