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. Sus2 is also often played exactly as add2 chords.
The shift from the original major chord to the sus chord is sometimes easily 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 has no shape that are close to the major. For Gsus2, also xx0033, which is primarily an option to shift between Gm (xx0333) with. Another options for Gsus2 are 300233 and 3X0233.
Chord constructionCsus2 x - C - D - G - C - x
Dsus2 x - x - D - A - D - E
Esus2 E - B - F# - B - B - E
Fsus2 x - x - F - G - C - F
Gsus2 x - A - D - G - D - G
Asus2 x - A - E - A - B - E
Bsus2 x - B - F# - B - C# - F#
Guitar versions of the chord
Notes in chordCsus2 C - D - G
Dsus2 D - E - A
Esus2 E - F# - B
Fsus2 F - G - C
Gsus2 G - A - D
Asus2 A - B - E
Bsus2 B - C# - F#
The intervals are 1 – 2 – 5
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.
More examples of progressions including a sus2 chord:
F - Fsus2 - F - C - Csus2 - C
G - Gsus2 - G - Csus2 - D
Dm - Dsus2 - Fmaj7 - Am7 - Csus2
Bm - Bsus2 - Bm - Bsus2 - F#m
There are no Amsus2, Bmsus2, Cmsus2 chords and so on, but as seen in some of the progressions above, it is possible to combine minor chords with suspended 2nd chords as well.
The connection between sus2 and sus4
The sus2 and sus4 chord types are the most common suspended chords. Actually, sus2 can be seen as an inversion of sus4:
Csus2 (C-D-G) is an inversion of Gsus4 (G-C-D)
Dsus2 (D-E-A) is an inversion of Asus4 (A-D-E)
Esus2 (E-F#-B) is an inversion of Bsus4 (B-E-F#)
Fsus2 (F-G-C) is an inversion of Csus4 (C-F-E)
Gsus2 (G-A-D) is an inversion of Dsus4 (D-G-A)
Asus2 (A-B-E) is an inversion of Esus4 (E-A-B)
Bsus2 (B-C#-F#) is an inversion of F#sus4 (F#-B-C#)