I'm not quite sure exactly what your wanting to oil, but I'll try. For the blade or any metal, any oil will work. 3 in 1, WD40, gun oil, you name it. For the handle, it depends on whether it's wood or horn. If it's horn, Hooflex or mineral oil work. I prefer to soak horn overnight in a jar filled with mineral oil. Do this every so often, depending upon climate (dry = more often). If it's wood, be sure it's finished with something like Tung Oil, Danish Oil, or Boiled Linseed Oil. You can also soak wood in mineral oil, but IMHO regular maintenance with a good wood finish is ideal. So, if it's horn handled, then mineral oil is the way to go for everything as it's cheap, food safe, and works great. Add wood treatment if appropriate.
I would clean the blade with oil and a Scotchbrite pad after use and oil/finish the handle twice a year or so. Hope that helps.