A transaction hash (also called a transaction ID) is a unique set of characters assigned to every blockchain transaction. Block explorers like etherscan.io or ethtx.info can be used to review a transaction.
The transaction hash is best sent by copying/pasting from your wallet or a block explorer. Sending screenshots of transactions can distort and pixelate the transaction ID characters. Sending screenshots may delay a support agent's resolution to your issue.
It's recommended to double check that you've copied the hash correctly.