How do i create a credit note

Hello Helen-Clark 

Welcome to the Community page, 

The way to create a credit note is the plus icon> under customer is credit note> it will open the credit note where you can fill out all the information and save. 

The way to link this to an invoice is, create the invoice>receive payment it will have the invoice ticked and scroll down it will have the credit note ticked as well>save and close and this will link them together.