Apple introduced both the iPhone 6 and iPhone 6 Plus few hours back. Both the iPhone models look exactly similar, have the same anodized aluminum back, new curved design, Apple A8 processor with M8 motion coprocessor, Touch ID fingerprint sensor, NFC and more.

These main difference it the screen size. The iPhone 6 has a 4.7-inch
(1334 x 750 pixels) screen, while the iPhone 6 Plus comes with a 5.5-inch (1920 x 1080 pixels) screen. Apple is calling it as Retina HD display.

The iPhone 6 Plus also comes with optical image stabilization (OIS) and a larger battery offering better battery life compared to the iPhone 6. On the software side, both these have Reachability, a new feature that move the UI halfway down the screen to reach easily just by double tapping the home button. The iPhone 6 Plus has landscape mode that offer two-pane view for apps. Check out the detailed comparison of the specifications below.

Other difference is the price. The iPhone 6 costs $199, $299 and $399 with a two contract and $649, $749 and $849 without contract for the 16GB, 64GB and 128GB variants respectively. The iPhone 6 Plus costs $299, $399 and $499 with a two contract and $749, $849 and $949 without contract for the 16GB, 64GB and 128GB variants respectively. It goes on sale in select countries starting September 19th.


Source - http://thegadgetsfreak.com/apple-iphone-6-vs-iphone-6-plus-differences-and-comparison-in-specifications-and-features/

The iPhone 6 is the more compact variant with a 4.7-inch IPS display. See https://www.naijatechguide.com/2014/09/apple-iphone-6-specs-price.html