Cold wallet = offline storage. Think of it like a safe in your house vs cash in your pocket.

Hot wallet (exchange, MetaMask) — connected to internet. Convenient but riskier.
Cold wallet (Ledger, Trezor) — offline. Can't be hacked remotely.

My strategy:

• Small amounts for trading: keep on exchange
• Long-term holdings: move to cold wallet
• Never share your seed phrase with ANYONE. Not even "support".

I use Ledger Nano X. Cost about $150, worth every penny for peace of mind.