To add one contact to your group, please check this help center article.
For many contacts, you need to:
Export the group from Address Book
Add phone numbers to the group (via Excel)
Deduplicate (via Excel)
Upload to the Address Book
1. Export the group from Address Book Go to the group you wish to expand and click on
Your group has now been downloaded as a .csv. To open the file properly in Excel, please check this help center article.
Ensure the phone numbers are in the right format including country code. For more information check this help center article.
2. Add phone numbers to the group (via Excel) Add the phone numbers to the file by copying them in the right column.
3. Deduplicate the phone numbers In Excel, go to the tab “Data” and click -within Data Tools- on “Remove duplicates”. Select the right selection (note that when you’re using custom fields (i.e. “First name”) that when there is not an exact match with all columns it will not be regarded as a duplicate. So “Ben” with phone number +31611111111 will not be deleted if there is also a “Benny” with phone number +31611111111) Save the file (i.e. Save as “Contact list new.csv”)
4. Upload the group as a new list Go to the Address Book app and click on to upload the new group. For more information, check this help center article.