How to find PUK code number of SIM Card (mobile phone)

How to find PUK code number of SIM Card (mobile phone). Many people use PIN number for their phone to lock some of the stuff or features.But if you enter PIN number 3 times wrong then your SIM card is blocked and will ask PUK number

If you enter PUK code number 10 times wrongly then your SIM card will be rejected and you have to buy a new duplicate SIM for your mobile phone. Here are the steps to get PUK number for different networks -
Airtel:
create a new message from any Airtel number (of your friends or relatives), type PUK PhoneNumber and then send it to 121 (toll free number)
For all other networks:
Call to your customer care number from other SIM card of same network and tell your details to them. They will first verify that you are the owner of that SIM, so they may ask name as registered on form, last call number, billing address, email ID, numbers you recently called, numbers you recently messaged or any other personal details. So keep all these ready when you call, then they will provide a PUK number, enter it and your mobile will be unblocked.