Remember that the bitcoin exchange and the bitcoin wallet are not the same things. Bitcoin exchanges are similar to foreign exchange markets. The exchanges are digital platforms where Bitcoin is exchanged for fiat currency—for example, bitcoin (BTC) for U.S. dollars (USD). While exchanges offer wallet capabilities to users, it is not their primary business. Since wallets must be secure, exchanges do not encourage storing large amounts of bitcoin or for long periods. Therefore, it is advisable to transfer your bitcoins to a secure wallet. Because security must be your top priority when choosing a bitcoin wallet, opt for one with a multi-signature facility.
The public key is the location where transactions are deposited to and withdrawn from. This is also the key that appears on the blockchain ledger as a user’s digital signature, not unlike a username on a social media newsfeed. The private key is the password required to buy, sell, and trade the bitcoin in a wallet. A private key should be a guarded secret and only used to authorize bitcoin transmissions. Some users protect their private keys by encrypting a wallet with a strong password and, in some cases, by choosing the cold storage option; that is, storing the wallet offline.