The is a lot of blogs saying weird things on this particular Powershell command.
Here the right one.
$onrepm = get-credential
‘alias for the user’ | New-MoveRequest
-OutBound -RemoteTargetDatabase
‘local database’ -RemoteHostName
‘ewsurl’ -RemoteCredential
$onprem -TargetDeliveryDomain
‘localsmtpdomain’