If a hosted voice service has been purchased from an approved Microsoft partner, you can enable the service for each user by configuring the Lync-to-phone provider for the user account, and then adding the user’s phone number to the Office number field.
Use the following steps to enable a user for Lync-to-phone using the online portal:
1. Log on to the Office 365 Portal.
2. On the left side of the main page, click Users and Groups.
3. At the Users and Groups page, click on the name of the user to be enabled for Lync-to-phone to open the account properties.
4. On the left side, click Details, and then click Additional details to display the optional user properties.
5. Enter the phone number that will be used with the ...