How to Transfer Contacts from iPhone to iPhone using iCloud
1. Make sure that you are logged into the same iCloud account from your new phone, as you have been using in your old phone.
2. Make sure that you are connected to WiFi.
3. Now in your old iPhone go to Settings and choose iCloud. Check if the option of contacts syncing is toggled on.
4. After you have enabled contacts syncing, go to Storage & Backup and tap on the Back Up Now option. You have now created a backup of your contacts on the iCloud.
5. Now in your new iPhone just open the Contacts app and tap on the refresh button.
6. The contacts syncing will now begin and in a few minutes you will get all your old iPhone contacts on your new iPhone.