After joining a computer to AzureAD you will login with a user and will be automatically added as a local admin. The trouble is when logging with other users. These users will automatically set as users to the computer. From the Computer Management Console there is no way to add an AzureAD as when you click on Add and Locations, there is no location for the AzureAD. If you look at the current AAD user in the Computer Management and Local Users and Groups you will find the current user as AZUREAD\noel.pulis.
Luckily there is a way to add an additional AzureAD user as a local admin.
– Open CMD (Command Prompt) as Admin
– Type NET Localgroup Administrators AzureAD\additionaluser
Once this is ready, open the Local Users and Groups and you will find the AzureAD user part of the local Administrators Group.