Hi,
Is that posible?
Everything is possible theoretically. The question is why you can pay for it
For example, you can publish your username and password online in public site so everyone will be able to control your subscript. Possible? Yes! Smart solution? NO!
Let's try to find the balance between given full control to everyone and a big of secure 🙂
Where do you want the button? what GUI app do your users use?
Option 1: If your users use the portal then your can use this option;
(1) Create users in the Azure AD for each of your users.
(2) Navigate to the Virtual Machine in the portal -> on the left menu click on "Access control (IAM)"
(3) "Add a role assignment" to the Azure AD users and allow them to control the virtual machine
Option 2: If you are using your own application, then you can base the solution on single user in the portal. Manage the security of using the app, and in your app you can use PowerShell command in order to turn on/off the VM
If non of these options fit you, then please try to elaborate a bit more about how the user should control the VM and how you control the users security