The Process Deposits and Credits form can be opened from Bank Reconciliation form by clicking the plus button in the Deposits and Credits section. This form is use to to configure the Amount of the debit or credit entries and the Account ID that will serve as the contra account for Cash Account. In the Reference field, you may enter any description you would want to describe that transaction for easy tracking later on.
See Add New Misc Debits and Credits on Bank Reconciliation form to show you how this works.