Scenario:
you administer SharePoint Online Microsoft 365 tenant
business asks you to remove mobile phone numbers from SharePoint User Profiles:

Solution:

As a SharePoint administrator, you can do it:
1. Start Microsoft 365 SharePoint Admin Center
2. Navigate to More Features -> User Profiles -> Manage User Properties

3. Under “Contact Information” -> Mobile phone -> Edit

4. Uncheck “Replicable”, Save, wait a minute or two
5.
– Select “Default Privacy Settings”: “Only Me”
– Uncheck “User can override”
– Uncheck “Allow users to edit values for this property”
– Uncheck “Show in the profile properties section of the user’s profile page”
– Uncheck “Indexed”

6. Save