A hash (or the tx ID) is a unique address of your transaction in a blockchain. 

Mostly, the hash is a combination of digits and lower case (upper in Ripple) letters that represents a proof that money is sent. 

Whenever you make a payment, you receive a hash displayed in your wallet. 

It looks like this: Hash should be located in a blockchain. 

Our support team may ask you to provide a hash. 

Sometimes it’s required to find your payment and resolve your issues, if any.