Cold storage means keeping cryptocurrency private keys on a device that is never connected to the internet. A hardware wallet or an air-gapped computer are common examples.
A hot wallet is connected to the internet and convenient for frequent use. Cold storage is offline and used for long-term holdings. Most people use both.
Because the keys are offline, remote attackers cannot reach them. Even if your computer is infected with malware, the cold wallet remains protected.
Buy a hardware wallet, set it up, write down the recovery phrase, and transfer your long-term holdings to it. Keep a small amount in a hot wallet for spending.
Cold storage is the recommended practice for any crypto you do not plan to touch regularly.