What is the difference between TRC20, ERC20 and BEP20?

These are token standards on three blockchains: TRC20 on TRON, ERC20 on Ethereum and BEP20 on BNB Chain.

USDT exists on all three, with different fees and speeds. Both sides of a transfer must use the same network. Sending over the wrong network can lose your funds, so check before you press send, and consider a small test payment first.