Sus2 chords are formed with the second note in the chord lowered one step. In addition to sus2 there is sus4, that is some more common. If you see instructions to play a chord like Esus or Asus it is usually not sus2 but sus4 chords.
The shift from the original major chord to the sus chord is for the most part easy done. Below you can see that the difference from a major chord to its "sus2 version" is small:
C major Csus2
There are two differences: 1) on the fourth string the tone is lowered one step from E to D, 2) you don't play the highest open string because this is an E note. When shifting from C to Csus2 you only need to lift the long finger and you don't move the rest of the fingers.
Esus2 and Fsus2 might be preferable playing as bar chords with Asus2 shapes. Gsus2 could also be played as 300033.
The Tom Petty song "Feel A Whole Lot Better" makes use of sus chords in a riff:
A - Asus2 - A - Asus4 - A - Asus2 - A.
The song also includes the chords E , F#m, B, Bm, D and G.
Another example of a progression including a sus2 chord:
G - Gsus2 - G - Cadd2 - D.