How to transfer phone numbers from iphone to iphone

All you need to do is connect your iPhone to the system, launch iTunes, and go to its “Info” tab. From here, you can choose to sync your contacts from your iPhone to your iTunes. Choose to sync all contacts and click on the “Sync” button to make them available on iTunes.

Once you have your contacts backed up in iCloud, you can transfer them to your new iPhone: Ensure the new iPhone is connected to Wi-Fi and is logged in to your Apple ID. Go to Settings > Tap your username > iCloud > Toggle "Contacts" to enabled.