You can import contacts from either vCard (.vcf) files or CSV files.
To import contacts
Click Address Book
Optionally, select the group into which you want to import the contacts.
Select Contacts if you want to export all of the contacts in the Address Book.
Click the Import icon.
Click Browse and navigate to the contacts file that you want to import. Select the file, and then click Open.
From the Import group assignments drop-down list, select which address book the contacts should be imported to. The Replace the entire address book checkbox lets you delete all contacts from the selected address book before importing. Be careful with this option; the deletion cannot be undone!
Click Import.