When joining a conference call by phone, a moderator pin or access code will be required to have access to the call.
The moderator pin is used by the account holder or those in charge of hosting the call (you can have more than one host/moderator on a call). After entering in your moderator pin, you will gain access to the moderator controls, where you can mute others and initiate recording (for those with upgraded plans) via phone.
Keep in mind that you will need the moderator PIN to open up a conference call if you have the Waiting Room turned on.
To join a call as a moderator via the internet, ensure you are logged into your account and enter as you usually would within your browser or app.
Make sure that only one person is logged into the account. This support article explains how you can have multiple moderators connected via the web.
Remember, you do not need to begin a call by entering in a moderator pin; you can also start a call by using the access code if you don't have the Waiting Room feature active.