1. Conceptual difference: Composing generally refers to composing melody for lyrics; arranging generally refers to accompaniment for songs; composing music means writing down existing music and writing it into simplified notation, staff, etc.

2. Difference in order: composition comes first, then arrangement and composition.

3. Difference in difficulty: Arranging and composing music are more difficult than composing music.

Extended content:

Composition

Music professional terminology, composition (Composition, Musical composition will be used to describe composition in non-musical content). Refers to the act of creating music, or the process of creating music. It can also refer to the creator of a musical work. (Referenced in "The New Grove Dictionary Of Music & Musicians" [1])

Use the technical theoretical system of basic music theory, harmony, polyphony, orchestration, and musical structure to express the creator's musical thoughts method. Different countries and historical periods have different creative styles and technical methods, which can be roughly divided into Baroque, Classical, Romantic, and Modern styles.

Arrangement

"Arrangement", understood according to the use of vocabulary and working methods in my country's professional music field (as a common phenomenon), refers to the combination of music production (Music production) arrangement method.

It is not just the arrangement of music from the perspective of musical instruments and timbre matching, nor does it only refer to the production of sound effects using computers, software and hardware. This makes the word "arranger" more like a profession and a job title, rather than a certain musical concept and composition technique.

Reference material: Baidu Encyclopedia Arranger and Composition