'Patient charges' is an amount debited from your monthly schedule for any patient charges you have collected.
'Remissions' is an amount credited to your monthly schedule for patients who ordinarily would pay but are supported due to low income. E.g. the patient has a HC2 certificate or receives Income Support.
'Exemptions' is an amount that shows on your monthly schedule for information but is not credited or debited as the patient does not pay for their treatment. E.g. the patient is under 18 years of age or is pregnant.