Hi Keith_7,
Based on my assumption, you might have seen the phone number column when selecting the Address List rather than the contact list displayed in the picture you shared above:

Generally, unlike address lists in the address book which contains the Business Phone column, a contact list whose data is from your Outlook contact folder only includes three columns, name, display name and email address and this is not editable.
If you would like to find more fields of a contact in the Contact list, please click on an individual contact entry to open up a form with fields for more information, including company, mailing address, job title, phone numbers, etc. Or you can directly
check via outlook contacts.
Hope this can be helpful.
Best regards,
Yuki Sun
Please remember to mark the replies as answers if they helped.
If you have feedback for TechNet Subscriber Support, contact
tnmff@microsoft.com.