#ConvertTo-SecureString -String "yourpassword" -AsPlainText -Force | ConvertFrom-SecureString | Set-Content "password.txt"

$servicename = "yourcloudservice"
$username = "remotedesktopuser"
$securepassword = Get-Content -Path "password.txt" | ConvertTo-SecureString
$expiry = $(Get-Date).AddDays(1)
$credential = New-Object System.Management.Automation.PSCredential $username,$securepassword
Set-AzureServiceRemoteDesktopExtension -ServiceName $servicename -Credential $credential -Expiration $expiry