MIDI interfaces are a very useful tool for musicians to combine a wide variety of electronic instruments into one file. Essentially, MIDI is a standardized data transfer protocol for communicating various musical instruments, computers, controllers, and other devices. The interface itself appeared back in the 70s, but it still remains one of the main interfaces for working with musical instruments or creating music.
With the help of MIDI, information is encoded about actions that are performed on a musical device - pressing keys, buttons, etc. There is a standard MIDI file - SMF, which is read by all MIDI devices. A separate midi track is a kind of musical score, but at the same time, it contains all the nuances of individual performance. MIDI melodies can be created using special programs similar to sheet music editors.