Every fingering that fits a hand
x674
easy
bb99
hard
bb9x
easy
What is true of it
F♯sus4 is F♯, B and C♯ — 1, 4 and 5 counted from F♯.
These are also the notes of Bsus2/F♯. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
The easiest of the 3 fingerings below is x674: 3 fingers, held at the 4th fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
1 string stays silent.
Where its notes are on the neck
The brass dots are F♯, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
F♯sus4/B
4122
F♯sus4/C♯
x122
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.