A Esus4 chord contains the notes E, B, A. It is built from the suspended 4th formula 1 - 4 - 5, with E as the root.
How do you play Esus4 from an E major chord?
From open E major, take the finger off the G string (the major third, G♯) and instead fret the G string at the 2nd fret (A, the fourth). Everything else stays put. That single move turns E into Esus4 without lifting the rest of the shape.