First of all, your transaction needs to be confirmed by the blockchain. In most cases, Freewallet requires 10 network confirmations or only 3 for the BTC wallet. Usually, it takes about 20 minutes to process a transaction. There is a progress bar under your transaction to inform you about your transaction status.
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, and then for each subsequent block.
Although for a low-value transaction a single confirmation may be considered secure enough, larger amounts, such as $1000, for instance, often need 6 or more confirmations.
Each confirmation exponentially decreases the risk that a transaction will be reversed.