Barre chord
fret 4, A shapex46654
C♯m is the C♯ minor chord. Its notes are C♯, E and G♯. It is the same chord as D♭m. The lowered third gives this triad its darker color.
x46654
9-11-11-9-9-9
Numbers show frets from the low E string to the high e string; x means don't play that string.
C♯m is the ii chord in B major, the iii chord in A major and the vi chord in E major. That makes it a natural fit in songs written in those keys.
Every C♯, E and G♯ on the first 12 frets. The filled dots are the root, C♯. Build your own shape from any nearby group.
Other C♯ chords
Other minor chords