To transfer coins in blockchain, you need to create a transaction using your private key to authorize the transfer. A private key is a secret alphanumeric code used in cryptography, similar to a password, that is used to authorize transactions and prove ownership of a blockchain asset. When you first buy cryptocurrency, you are issued two keys: a public key, which works like an email address and can be safely shared with others, and a private key, which is like a password and should not be shared with anyone. Private keys represent the final control and ownership of cryptocurrency, and if they are stolen or lost, your crypto is gone.

To create a private key, you can use various cryptographic functions. Private keys can take a few different forms, but they are usually expressed as a string of alphanumeric characters. When you generate a private key, you want to be extremely secure, as anyone who learns the private key can easily steal all the coins from the corresponding wallet.

In summary, to transfer coins in blockchain, you need to create a transaction using your private key to authorize the transfer. To create a private key, you can use various cryptographic functions, but you need to be extremely secure to prevent theft of your coins.