We need your transaction to be confirmed by the blockchain. In most cases, Freewallet asks for 10 network confirmations (only 3 for BTC wallet). Usually, it takes about 20 minutes to finish a transaction. You'll have a progress bar under your transaction to inform you about your transaction status (Pending).
Confirmation means that a transaction has been processed by the network and is highly unlikely to be reversed. Transactions receive a confirmation when they are included in a block for each subsequent block. Even a single confirmation can be considered secure for low-value transactions, although for larger amounts like 1000 US$, it makes sense to wait for 6 confirmations or more. Each confirmation exponentially decreases the risk of a reversed transaction.