BEP-20
In short BEP-20 is the token standard on BNB Smart Chain, essentially the same as ERC-20, with fees paid in BNB instead of ETH.
BEP-20 is the standard for fungible tokens on BNB Smart Chain, often just called BNB Chain. It mirrors Ethereum's ERC-20 almost exactly, with the same core functions like transfer, approve, and balanceOf. Because BNB Smart Chain is EVM-compatible, a contract written for Ethereum can usually be deployed there with little or no change.
Mechanically, a BEP-20 token is a smart contract that keeps a ledger of who holds how much. Wallets and DEXs on BNB Chain read and update that ledger through the standard functions. Every transaction pays gas in BNB, and fees are typically much lower than on Ethereum mainnet, which made the chain a popular home for small and experimental tokens.
For holders, the key point is that a BEP-20 token is a different asset from an ERC-20 token with the same name. Many projects deploy on both chains, or use a bridge to create a wrapped version, and each has its own contract address and liquidity. Sending a BEP-20 token to an exchange deposit address that only supports Ethereum can lead to lost or stuck funds, even though both use 0x addresses.
Low fees cut both ways, since they also make it cheap to launch copycat and scam tokens. Check the contract on BscScan for verified source code, owner privileges, mint functions, high transfer taxes, or blacklists. Look at whether liquidity is locked and how concentrated the top holders are. Keep a small amount of BNB in your wallet for gas, and always pick the BNB Smart Chain network explicitly when withdrawing from an exchange.