Trading operation on Binance (in short):

Place an order – User selects crypto pair (e.g., BTC/USDT) and places a buy or sell order.

Order matching – Binance’s system matches it with the best available counter-order.

Trade executed – Once matched, the trade is completed instantly.

Balance updated – The user's wallet reflects the new asset amount.

Trading fee – A small fee is deducted per trade (often less with BNB).

In short: Users place orders, Binance matches them, executes trades, and updates balances—all automatically and in real-time.