This update adds an access code in the meeting invitation template in Microsoft Skype for Business 2016. You can input the conference ID by clicking the PSTN number that's inside an email message or a calendar invitation to join the meeting.
Note The feature is disabled by default. You can turn on the feature by creating a new OneTapJoinForPSTNCallingOnMobile Group Policy Object (GPO), and then set its value to 1. The registry type of the GPO setting is DWORD. The setting is located in the following registry subkey:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Lync\AddinPreference
Click here for detailed steps about how to turn on this feature in the "More information" section.