Italian bureaucratic language is pretty strange. You can sign and stamp a document, but this act has a different value depending on when it's used. The 'Visto' is attached to a so-called "atto perfetto", in other words a document that has already been signed and sealed/stamped and so 'concluded'. (It's one of four possible options: 'sigla', 'visto', 'firma' or 'sottoscrizione').

The correct punctuation should be VISTO: Si trasmette...

Have a look at this example:
http://www.comune.arcore.mb.it/upload/arcore/dip_inc/decreto...

You'll see that the document is already signed and stamped by the municipality. The 'visto' is the separate bureaucratic step of forwarding the finished coument to the Prefecture of Milan.

In this particular case the dicuments are being forwarded to the PM (prosecutor), who works in the same court, not because it's a criminal case or that the PM needs to prosecute anything, but because the case involves a minor and the PM has to be involved, by law, and as form of guarantee from the court's point of view.

The additional lines express the various reasons why the documents might be forwarded 'per competenza, per esame parte, lesa, per indagini, per interrogatorio, per l'unione agli atti trasmessi'.

I think they're pretty evident: 'per competenza' here means that the PM is competent to handle the papers, i.e. needs to see them for official reasons. 'Unione..' just means the document sent should be added to the (bundle of) other papers sent.

Are you sure it's "per esame parte, lesa" and not "per esame parte lesa"?