Transaction hash (txid) is an identifier used to uniquely identify a particular transaction. All on-chain transactions (the transactions from or to external addresses) have a unique txid that can be seen in transaction details. A transaction hash usually looks like a random set of letters and numbers. All on-chain transactions (depositing and withdrawing of funds) have a unique txid that can be found in transaction details.
In Freewallet apps
Tap on a transaction > Search for Hash in the list > Check your transaction in the blockchain.
In other services
Get transaction details and search for something like Transaction ID, TXID, Transaction Hash etc.
The hash example:
You might have a link from a platform like etherscan.io, like this:
If you have one, you'll need all the symbols after "tx/". For example, in the link above the hash is 0x2446f1fd773fbb9f080e674b60c6a033c7ed7427b8b9413cf28a2a4a6da9b56c
If you have any questions regarding a deposit or a withdrawal, it is always useful to provide the transaction hash. This way, a support team agent will be able to locate and check the status of the transaction.