USDT exists as a token on multiple blockchains. - like for ex. bep2 token on BC / binance chain, bep20 token on BSC / binance smart chain and erc20 token on Ethereum.
Before transfer it is good to verify the smart contract address for the specific chain through etherscan or alike site, so that the address is for the real USDT and not for one of the dozens of other smart contracts created with the same symbol name.
Binance has a bridge page which allows transfers from/to BSC / BC / Ethereum.
The page tells about the network fee to be paid as well.