Yes, how can Multiple users access the same VM instance, wouldn’t that require 1 instance per user ? and then you would need the required license for each user.
Hi, think like you are login in inside your windows machine or Linux. The virtualization of your host inside Azure is done with a virtual machine that will carry the same functionality as a normal pc. this mean possibility to have multiple users with different username and password.
When the VM is deployed from Azure is presenting only one administrator account. You need to create the additional one if you need it.
The other difference is that with windows you have RDP available from the first deployment. With Linux remember that you have only CLI and if you want to enable a graphic interface to use RDP you need to install the correct modules.
I hope that this answers your question.