Part-writing is a type of exercise practiced widely in the United States. It serves the following purposes:

Helps students to understand the typical compositional approaches used by Western tonal composers.
Trains students in arranging and composition.
Provides practice opportunities for spelling and voicing chords.
Develops problem-solving skills.

Two formats are typically used for part-writing: SATB (soprano/alto/tenor/bass) format and keyboard format. As their names imply, SATB format is used in choral settings and keyboard format is used for piano. The example below shows the same progression in both formats.

SATB format follows these guidelines:

Voice names
- From top to bottom, the voices are soprano, alto, tenor, and bass.
- The top note is often called the melody.
- The alto and tenor are called inner voices.
Clefs
- Soprano and alto are notated in the treble clef.
- Tenor and bass are notated in the bass clef.
Stem directions
- Soprano and tenor are notated with stems up.
- Alto and bass are notated with stems down.
Ranges (roughly)
- Soprano: E4 to G5
- Alto: A3 to C5
- Tenor: D3 to F4
- Bass: E2 to A3
Distance between voices
- Between the soprano/alto and alto/tenor, there can only be an octave at maximum.
- Between the tenor and the bass, there can be any interval as long as both voices are within their respective ranges.

Keyboard format follows these guidelines:

Clefs and voice names
- The right hand is notated on the treble clef. The top note is often called the melody, while the two lower notes are called inner voices.
- The left hand is notated in the bass clef. This note is called the bass.
Stem directions
- The top note of the right hand is notated with stem up.
- The bottom notes of the right hand are notated with stems down.
- The left-hand note is notated following the usual stem direction rule.
  - The usual stem direction rule: Notes on or above the middle line of the staff get stems down. Notes below the middle line get stems up.
Because the music is performed on a keyboard rather than sung, the notes are not limited by range. However, the notes of the right hand must be playable by one hand. Therefore, there should be no more than an octave between the top and bottom right-hand notes.