Generally, you don't need to be proficient in music theory to record music. The ability to record the music you hear depends on the situation. Whether what you listen to is difficult or not, works like pop songs are usually not difficult. If you just listen to the main theme, it will be easier. You need to know the music score, the staff notation is ok, and then you need to practice the ability to distinguish sounds. Under normal circumstances, An untrained person's afternoon time is enough to record the main melody of pop songs. If you want a high level, you can record it after listening to it once, which takes a long time to exercise. Most musicians who can practice this level start training at a very young age, and then they can record such main melody after listening to it once in college.