First, ‘product’ Improvisation affects the outcome of what is done, whereas ‘process’ Improvisation changes the way something is done (Miner et al. 1997).
Second, ‘behavioural’ Improvisation refers to changing organisational actions, whereas ‘cognitive’ Improvisation gives new meaning to external stimuli (Miner et al. 1997). Third, ‘idiomatic’ Improvisation happens within an existing vernacular such as jazz music, whereas ‘non‐idiomatic’ Improvisation is completely free (Bailey 1992).

Allègre L. Hadida, William Tarvainen, Jed Rose (15/9/2014), ‘Organizational Improvisation: A Consolidating Review and Framework’, International Journal of Management Review’, https://onlinelibrary.wiley.com/doi/10.1111/ijmr.12047

Improvisation, by its nature, occurs at the intersection of action and cognition; it encompasses how people think and feel in the situations they exist in and how the relate to one another in the moment. Such practices do not have inherent levels of analysis and, in fact, can be used by scholars to link them (e.g., Bourdieu, 1977; Emirbayer & Johnson, 2008).

Colin Fisher and Frank J Barrett (5/2019), ‘The Experience of Improvising in Organizations: A Creative Process Perspective’, Academy of Management Perspectives’, https://www.researchgate.net/publication/328255742_The_Experience_of_Improvising_in_Organizations_A_Creative_Process_Perspective

Limb and Braun discovered that during the improvised riffs, the jazz musicians medial prefrontal cortex, the area of the brain associated with language and creativity significantly increased in activity, whereas their dorsal lateral prefrontal cortex, the conscious control part where you judge and correct your behavior became dormant.
Fascinated by these results, limb has gone on to carry out similar studies with freestyle rappers, and most recently, with Improvisational comedians with very similar results.

Max Dickins (14/7/2021), ‘Improvise!: Use the Secrets of Improv to Achieve Extraordinary Results at Work – Chapter 3: spontaneity’, Icon Books’, PDF