A Dsus2 chord contains the notes D, A, E. It is built from the suspended 2nd formula 1 - 2 - 5, with D as the root.
How do you play Dsus2?
Take the open D major shape and lift the finger off the high E string (removing the third, F♯), leaving that string open (E, the second). You're left with D on the D string, A on the G string, and the open high E — a clean, floating Dsus2.