A "watchdog" to monitor a specific folder for an event like "created, changed...". To get this automatically running it has to be included in the windows tasks.

example.csv

CustId	Straße	PLZ	Ort
123	D-Str. 5	52080	Aachen
456	Am Keller 2	61080	Bad Vilbel
789	Kaiserstraße 35	60329	Frankfurt am Main

filewatcher.ps1

# create filewatcher object
$watcher = New-Object System.IO.FileSystemWatcher 
$watcher.Path = "C:\Users\Florian\Desktop\20181216\filewatcher"
$watcher.IncludeSubdirectories = $true
$watcher.EnableRaisingEvents = $true
$watcher.Filter = "*.csv"

# show possible events
$SupportedEvents = $watcher | Get-Member | where {$_.membertype -eq 'Event' }
$SupportedEvents

# This defines what happens when the event "Created" happens.
Register-ObjectEvent $watcher -EventName Created -Action {
    
    # This is the triggered event
    $e = $event
    ( $e.TimeGenerated,$e.SourceEventArgs.ChangeType,$e.SourceEventArgs.FullPath ) -join ", " | Write-Host

    # Definition of im- and export data
    $importfile = Get-Item -Path $e.SourceEventArgs.FullPath
    $exportfile = "$( $importfile.Directory.Parent.FullName )\export.csv"
    Remove-Item -Path $exportfile -Recurse

    # load and export data
    $csv = Import-Csv -Path $importfile.FullName -Delimiter "`t" -Encoding UTF8
    Write-Host $exportfile
    $csv | Select custId, PLZ | export-csv -Path $exportfile -Encoding UTF8 -Delimiter ";" -NoTypeInformation

}
#Register-ObjectEvent $w -EventName Deleted -Action { a $event "red" }

# This loop keeps the script running
while ($true){
  Start-Sleep -Seconds 10
}

# to remove all of the watchers, run below. This is assuming you don't have any other 
# event subscriptions you want to keep live. If so, you probably already know what to do. =)
Get-EventSubscriber -Force | Unregister-Event -Force