Add-Type -Path 'C:Program FilesMicrosoft Azure Active Directory ConnectMicrosoft.IdentityModel.Clients.ActiveDirectory.dll'

$tenantID = "<the tenant id of you subscription>"
$authString = "https://login.windows.net/$tenantID"

# It must be an MFA-disabled admin.
$username = "<the username>"
$password = "<the password>"

# The resource can be https://graph.windows.net/ if you are using graph api.
# Or, https://management.azure.com/ if you are using ARM.
$resource = "https://management.core.windows.net/"

# This is the commond client id.
$client_id = "1950a258-227b-4e31-a9cf-717495945fc2"

$creds = New-Object "Microsoft.IdentityModel.Clients.ActiveDirectory.UserCredential" -ArgumentList $username,$password
$authContext = New-Object "Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext" -ArgumentList $authString

$authenticationResult = $authContext.AcquireToken($resource,$client_id,$creds)