What is the cold storage wallet?
cold storage wallet keeps all the private-key data on the offline computer, only someone with physical access to the offline computer can can have access to the BTC stored in it.
in general cold storage wallet are offline wallets.
How to do that?
Methods of cold storage include keeping bitcoins:
#1 On a USB drive or other data storage medium in a safe place (e.g. safe deposit box, safe)
#2 On a paper wallet
#3 On a bearer item such as a physical bitcoin.
#4 Online, but on encrypted media where the encryption key is offline.
#5 Use a offline Bitcoin Hardware wallet