How to import contacts from one to iPhone to another
Contacts
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If you use iCloud with contacts, all of your contacts will sync from one phone to the other one. This is assuming that you are using the same Apple ID on both phones.
Settings>Your Name>iCloud>Apps Using iCloud>Contacts>On.
If you are setting up a new phone and you want that phone to be clone of your old phone, your can restore the backup of the old phone in order to transfer all data and settings to the new phone.
Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support