Do you mean a sticker? Not having a Hobbycraft here I'm not sure what you're describing.
If it is a sticker, why not just ger clear labels - remembering to e sure you get laser ones for laser printers (and make sure that you get suitable for colour or mono printers as required) or ones for inkjet.
I know that Avery do them (or did, it's been a while since I bought clear ones).
As for software, you can print labels from any program. Why not download Open Office - is free and is mac comparible. Then just play with different fonts - and there are loads of free fonts on the internet, again mac compatible.