To understand what coaching really is, we can start from the end, i.e. think about its consequences.
Let's try to ask ourselves what purpose coaching is intended for.
What can a person aspire to when addressing another person by embracing the principles of coaching.
Generating change in the client is the goal of coaching.
We usually talk about behavioral change (e.g. your autonomy).
But there is a higher type of change to which he aspires, which is the change of mentality, of the premises that everyone carries within.
In other words, a coach doesn't just try to change what you do (behaviours), but since he's there by your side, he also tries to change who you are, your mentality, your beliefs, as if he were thinking within himself:
"And if I can do this, if you embrace a new mentality, tomorrow you will be able to solve your problems better even without me".
A coach tries to make himself unnecessary, in other words.
In short, behaviors and mentality are the two dimensions in which coaching seeks to produce an impact, because if the person who benefits from coaching behaves in a way that is more functional to their well-being, and if they adopt a more suitable mentality to make them live to the fullest , he is more likely to achieve the goals he sets for himself.
If you want to learn more about these concepts, here is a reference model on behavior and mindset change.