This usually takes a few minutes after the transfer appears on chain and can take longer when the network is busy; the Deposit page always shows the current number of confirmations needed.
In Wallet, under History, a deposit moves through Pending, Confirming (with a count such as 12/20 confirmations), Confirmed and Credited. Credited means the USDT is in your available balance.
A deposit below the minimum is not credited automatically: it shows Under review with a note, and our team reviews it. If deposits are temporarily paused, new deposits are still detected and are credited after the pause ends. If a transfer you sent doesn't appear in History, contact support with its transaction hash (TXID).