How to set up a conference call on an iPhone

With conference calling, you can talk with up to five other people at the same time.

To start a conference call:

Place a call.
From the in-call menu, tap Add Call. While you dial the second number, the first call will be placed on hold. If you don't see the in-call menu, tap the Hide Keypad button to bring it up on the screen.
Once you have the other person on the line, tap Merge Calls to connect everyone.
Repeat steps two and three to add other people to the conference.

For more help with this feature, or for other tips and tricks, visit the Apple website.