The Cisco IP Phone 7800 Series Quick Start Guide and Cisco IP Phone 8800 Series Quick Start Guide covers essential features including transfers, conference calls, call on hold, and forwarding.
DIT offers support articles covering the setup and use of phone features in more depth. You can search for support articles on the DIT support website. To setup and use any of the phone features, first log into the Cisco Self Care Portal.
If you need specific information not found in the start guide, Cisco has a comprehensive database on 7800 series support and 8800 series support about how to troubleshoot, install, add accessories, security information, and more.