Whenever you send crypto to an external wallet address, your transaction will have a specific Transaction ID (TXID), which consists a long string of numbers that identifies your transaction on the blockchain like a digital receipt. The person you're sending the crypto to might request your TXID to prove that it has been sent successfully.
Here are the 2 easy steps to find your TXID:
You'll then see a list of all of your transactions, including the Transaction ID for each.