To learn more about your iPhone 6 refer to the guide included in your device box to help iPhone 6 and iPhone 6 Plusyou get started, or check out this

a) iPhone 6 Manual User Guide: http://www.iphone6manualguides.com/

or

b) iPhone iOS8 User Manual provided by Apple: http://manuals.info.apple.com/MANUALS/1000/MA1565/en_US/iphone_user_guide.pdf 

If AT&T is your cell phone provider, visit the Phone & Device Learning Center at www.att.com/WirelessSupport for Consumers and at www.att.com/Biz for Business Customers, where you’ll find videos and step-by-step tutorials about your phone and its features.