When users join Cisco Webex Meetings meetings, events, or sessions using only their phone, their phone number is not displayed. You can turn this feature on so a partial caller ID shows.
From the customer view in https://admin.webex.com, go to Services, and under Meeting, select Sites.
Choose the Webex site to change the settings for, and click Configure Site.
Under Common Settings, select Site Options.
Check the Display Caller ID for dial-in users when available check box, and then click Update.