$clientId = "clientId GUID"
$appDomain = "App Domain"
$appName = "Friendly Name"
$appUrl = "App Url"
$newClientSecret = "Client Secret"

$servicePrincipalName = @("$clientID/$appDomain")
New-MsolServicePrincipal -ServicePrincipalNames $servicePrincipalName -AppPrincipalId $clientID -DisplayName $appName `
  -Type Symmetric -Usage Verify -StartDate "12/01/2016" -EndDate "12/01/2017" -Addresses (New-MsolServicePrincipalAddresses -Address $appUrl) 
New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Symmetric -Usage Sign -Value $newClientSecret
New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Symmetric -Usage Verify -Value $newClientSecret
New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Password -Usage Verify -Value $newClientSecret