From the home screen, press ‘select a carrier’. 2. Select Royal Mail Domestic. 3. Now page down until Pre-Paid Reply is shown. Select this option. 4. Select 1st or 2nd Class 5. Select either Letter or Large Letter PLEASE NOTE: You can only send letters this way, not parcels. PLEASE NOTE: This only applies to Mailmark compatible franking machines. PLEASE NOTE: The maximum weight of a prepaid reply 100g