You use the Fin. Charge Comment Line table to set up comments you want to attach to specific finance charge memos.
This table is displayed in the Comment Sheet window, which you find from the finance charge memo by clicking Memo and then choosing Comments or by clicking the button with the pencil icon on it.
Note that comments on finance charge memos are copied to the Issued Fin. Charge Memo Header table when the finance charge memos are issued.