i am not able to import contacts from my Samsung Galaxy S3 to Iphone S5 using icloud & VCF format

You will need to export the contacts from the Galaxy in a supported format for the phone. If you can sync them to the computer and Outlook, or Address Book, and then sync them to the iPhone via iTunes. If the contacts are in G-mail, you can also get them to the phone via a sync to the G-mail account. Try this way to import contacts from Samsung Galaxy S3 to iPhone 5s.