At an engraving shop, you can get your items engraved by an npc.
engrave <text> on <object>
request <type> insignia on <object>
Chiz-Hul-It's Engraver's stall can be found in the Djelibeybi bazaar (look for "A dark and musty stall appears to be trying to hide away from the noise." at the end of the room description). He charges &&&&&&&&&&&&&+80 per letter (spaces are free). The engraved text will be in Djelian.
Mr. Cranwell's Engraving Shoppe is in Ankh-Morpork, near the west end of the Street of Cunning Artificers. He charges &&&&&&&&&&&&&+80 per letter (spaces are free) and engraves in Morporkian. He can also engrave insignias, for &&&&&&&&&&&+3000 each:
The following options are available: pattern of mystical symbols Conlegium Sicariorum coat of arms Assassin Thieves' Guild coat of arms thief Fools' Guild coat of arms witch Unseen University coat of arms priest koi carp warrior snarling tiger frog crane dragon lotus blossom dragonfly water buffalo wasp viper phoenix scorpion horse tree frog cow black widow wolf cobra pair of crossed swords raven dagger Palace Guards' coat of arms coat of arms
Text engraved by npcs looks like this:
You read the silver ring: Written in neatly engraved letters in Agatean: Sto Lat
Insignias look like this:
A wasp is engraved onto it.