Barre chord
fret 2, E shape242322
F♯7 is the F♯ dominant 7 chord. Its notes are F♯, A♯, C♯ and E. It is the same chord as G♭7. A major triad with a flat seventh. Try G7 resolving to C.
242322
x-9-11-9-11-9
Numbers show frets from the low E string to the high e string; x means don't play that string.
F♯7 is the V7 chord in B major. That makes it a natural fit in songs written in those keys.
Every F♯, A♯, C♯ and E on the first 12 frets. The filled dots are the root, F♯. Build your own shape from any nearby group.
Other F♯ chords
Other dominant 7 chords