I ask for partials electronically now, always as a word .doc attachment.
Most of you send me files labelled title.doc.
some of you don't.
recently I got:
title-fixed.doc (you neutered the poor thing!)
partial Janet.doc (what part??)
and my fave so far
R-I-P.doc (which as far as I can tell was Reid-Imprint-Partial...but who knows)
There are no hard and fast rules on this; it just amused me.
One thing I have learned the hard way though is numbering and dating the versions of things I'm going back and forth on. That was a painful lesson let me assure you.