A private key is like a password. Don’t share it with anyone. Keep it safe. Cryptocurrency is about individuals owning their assets, which means they have to take responsibility for them. You may have heard the horror stories of Bitcoin users losing their keys... Don’t be that person!
A public key is like an ID, which is used to send and receive cryptocurrencies or tokens to your wallet.
When you initiate a transaction, you sign it with your private key. Then, the proposed transaction is broadcast to the network of blockchain nodes.