This app is the best FREE app for your contacts. 1. Help you to backup/restore/import/export your contacts to/from iCloud 2. CHECK and MERGE duplicated contacts 3. Add/remove the country code 4. Format phone numbers 5. Delete all contacts 6. Export contacts to Excel file 7. Share your contacts 8. Send SMS/Mail to a list of selected contacts. 9. Do you want to change the prefix of numbers in your contact list? See example: Number: 0935675680 Old Prefix: 0, New Prefix: +84 => New number: +84935675680 Number: +84935675680 Old Prefix: +84, New Prefix: 0 => New number: 0935675680 Number: 0935675680 Old Prefix: (Empty), New Prefix: +84 => New number: +840935675680