if you want to do content approval automatically done for document libraries , here is the set of PowerShell commands
EnableModeration is the property that needs to set true.
foreach($web in in $site.AllWebs){
foreach($List in $web.Lists){
if(($List.BaseType –eq "Document Library" ){
$List.EnableModeration=$true
}
}
$web.Dispose()
}
$site.Dispose()
Hope it helps. Happy SharePointing :-)