Crypto wallet
In short A crypto wallet holds the private keys that let you sign transactions and control your tokens on a blockchain. The coins themselves stay on-chain.
A crypto wallet is software or a hardware device that holds the keys controlling your addresses on a blockchain. It does not store coins the way a physical wallet holds cash. Your tokens exist on the chain itself, and the wallet keeps the private key that proves you are allowed to move them.
Mechanically, a wallet generates a private key and derives a public key and an address from it. When you send tokens, the wallet signs the transaction with the private key, and the network verifies that signature without ever seeing the key. Most wallets create their keys from a seed phrase, usually 12 or 24 words, and that phrase can restore the accounts derived from it in any wallet that supports the same standard. Support varies by chain and wallet, so a phrase does not automatically bring back every account everywhere. Address formats also differ: one Ethereum-style address works on Ethereum, BNB Chain, and Base, while Solana uses a different format.
The real issue is custody. In a self-custody wallet, no exchange or company holds your keys, so nobody can reset your password or recover the account for you. That removes a custodian's control, but not every outside control: the issuer of a token such as USDC can still freeze it at the contract level. If you lose the seed phrase but the wallet still opens, you can move your funds to a fresh wallet. The funds become unreachable when you lose both the device and every backup of the phrase, and anyone who gets the phrase can empty the wallet within minutes.
Write your seed phrase down offline, and never type it into a website, photograph it, or store it in cloud notes. No legitimate support team will ever ask for it. Read what you are signing, especially approvals that let a contract spend an unlimited amount of a token. A hardware wallet keeps your keys away from your computer, but it cannot tell whether a transaction or approval you confirm is malicious, so it does not prevent that kind of loss. Keep a separate wallet with a small balance for unfamiliar tokens, install wallet apps only from official sources, and send a small test amount first when using a new address or network.