HI Ariman,
Thank you for choosing AkrutoSync.
Akruto can sync your Outlook notes directly to the native notes of app of an iPhone 5. No need to download a 3rd party application that can sync notes for you on your phone.
You can try out the software and see if it works for you. You can download the 7-day free trial here:
https://www.akruto.com/get-akruto-sync/
Regards,
Brian Tan