Depending on the piece, I sign my name, the date of completion, etc.
in a variety of manners.
On rings, I usually stamp in my hallmark, karat marks etc. in a
place up towards the side or top 1/2 of the ring to allow for sizing,
engraving, etc. On my brooches, neckpieces, etc-- anything that might
be hollow-- I usually stamp whatever info I want onto a small sheet
of metal (cut or shaped to best compliment the area it is being
applied to) and solder this "tag" in place. Sometimes you need to
curve the sheet after stamping to fit, say, a tubular surface.
Another method I use, most often on earrings, where I don't want the
added steps of applying a "tag", I sign the piece with the same info
used above using a .4mm round or ball bur in my flex shaft. Since I
use a Techno X handpiece it's like writing with a fat pencil that
always wants to pull to the right. With a little practice and a
sharp bur it is a great way to sign a piece: No marring of the front
or back (if you're careful), no solder clean up and no vibration.
Hope this helps,