SIM card is locked how can I type a PUK-code?

put the sim card in a phone and type in the puk code and put it back in the ipad

even with a motorola in the 90's I had to use a nokia to apply the puk code

think sim codes and puk codes are not sued much in some places since both apple and motorola have issues with them in terms of using puk code and also with sim cards set to request sim pin code at start up

You may have to contact your carrier if your Sim Card is locked and you don't remember your PUK-Code.

Check this article out http://support.apple.com/kb/HT1316

Hope it helps.

Let me know.