Where Do Accidentals Go?

Accidental, in music, sign placed immediately to the left of (or above) a note to show that the note must be changed in pitch. A sharp (♯) raises a note by a semitone; a flat (♭) lowers it by a semitone; a natural (♮) restores it to the original pitch.

Where do you put accidentals?

Accidental of suspended note is nearest to the notes; highest accidental is further left; lowest accidental is farthest left. Highest accidental is closest to notes; accidental of suspended note is farthest left; other accidental is in between. Same placement as above.

Do accidentals apply to the whole bar?

The accidental will apply to following notes in the same measure / bar but not after that. If it is needed to cancel the effect before then another accidental (maybe a natural sign) will be required. Oddly, although a sharp or flat in the key signature affects the same note in other octaves, an accidental does not.