You can find a transaction ID (txid) by entering your wallet and going to your transaction history, more specifically you can look at your transaction history for a specific virtual asset. From here you should be able to view all sent and received transactions from the selected wallet. You can click on the transaction ID and get all the information on the blockchain from a block explorer which correlates to the currency you have sent or received. From here you will be able to view the details of the transaction including the status of the transaction, the timestamp, the sending and receiving address including the value, transaction fee and gas price if relevant.

A transaction ID is an alphanumerical code that identifies a specific transaction on the blockchain, it acts as a record or proof that the transaction has taken place.