A E Major 6 (E6) chord contains the notes E, B, G#, C#. It is built from the major 6th formula 1 - 3 - 5 - 6, with E as the root.
Is E6 hard to finger?
It uses all four fingers, which catches people out coming from open E. The trick is to set the E major shape first with index, middle and ring, then add the pinky at the 2nd fret of the B string. Once the hand knows that position the chord is no harder than E major — it just has one more finger in play.