Thanks for your reply .

I understand the purpuse of credit memos and refund receipts. 

1- What i don't understand is the process to issue the refund. Why would i need to create a memo first. For example +$100 credit . And then issue a refund of - $ 100 ( negative)

2- why does it show the negative balance at the bottom ? Does the negative mean that a refund has been issued ?  Cause when i create an invoice of $ 100 , the balance is 100. 

Then i receive payment of $ 100. Now the balance is 0 ( since it is all paid ) 

Then when i issue the refund, it shows - $100. Does the negative just means that the balance was paid in full but a refund was issued and it stays negative and that is just how qb operates or it should be zero ?