• Go to Dashboard > Bills
• Tap on the bill to be marked as PAID from OVERDUE or UPCOMING tab
• Bill detail screen will appear
• Tap on 'Mark Paid' icon
• Payment screen will appear.
• Select the from account (Account from which bill payment is being done)
• Add your payment date.
• Switch from Full Payment to Partial Payment tab.
• This will show a Partial Payment confirmation.
• Confirm the partial payment as OK 
• Check if you want to create an expense entry for this bill.
• Tap on done icon on top right corner and bill will be marked as partially paid.
• Partial paid amount entry will be shown in PAID tab and remaining due bill will also be available in Up-Coming/Overdue tab.