The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
Process note
Serum, Sylenth1, Addctive Keys, Flex.
Melodic loops
Instrument Guitar Atm
Sample pack Soul Surplus - Neon Lights: Modern R&B
Loop name SOULSURPLUS_neonlights_melodic_loop_8_eletric_guitar_lead_Reverb_rnb_120_bpm_Gmaj