Since every user created under a virtual graphic workstation deployment gets their own dedicated VM (Virtual Machine), to edit a user means making changes to their VM.
You have two options to edit the VM:
From Users module under Cloud Desktops section
Just click on the user to open details
User details will be displayed, just click on the VM name
In the edit window you can change the VM description, open ports in the Firewall section or manage the resources on the right. If you change the instance type and the amounts of RAM and CPU, make sure that the GPU type assigned to the instance can still cover your increased CPU and RAM amounts. You can learn more about available vCPUs and memory here.
2. Another way of getting to the editing options for the VM is directly from VM Instances module under Cloud Manager section
Edit user details
To edit user details such as email address or name, click the Edit button with the pencil icon: