The B suspended fourth chord is a 3-note chord consisting of the notes B, E and F#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Bsus4.
Chords that are a superset of Bsus4. The chords include more notes but always B, E and F#.
Chords that are a subset of Bsus4. These contain less notes but all of them are included in Bsus4.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Bsus4 chord. Feel free to save or share the image as needed.