Organization structure

Yes, more or less. Functional really describes the shape of the organisation - divided into functional departments. Within each department there could be great discretion given to employees about how to do their jobs - that would not be bureaucratic. However that is rather rare and the functional structure usually has a strict hierarchy within each functional department, so becomes very bureaucratic.

I see, so a company become bureaucratic instead of functional, the criteria to determine was based on the level of control, monitoring etc is it? If the company was under normal supervision, is it still known as functional? Can illustrate to me by example? Thank you.

As I said, functional and bureaucratic describe different things and are not mutually exclusive. A functional organisation could be very bureaucratic (ie lots of forms to fill in and close supervision). Government departments are typically like that. However, it is possible for a functional organisation (eg separate departments for accounting, sales, purchases etc, each department fulfilling a function) but within each department, bureaucracy could be low and people would be expected to largely manage themselves and would be given discretion to ensure work is carried out properly.