At the time of the audit, quality objectives at relevant functions were not available. So what do i say could be the root cause and corrective action proposed?
Was this your certification audit? If it was, and there were no quality objectives established, that's a serious deficiency, given that it clearly statesin the Standard that you need some measurable objective.
I cannot tell you what your root cause was - there's simply not enough information. Did you not read the Standard? Not understand what it meant? Don't know how to set them? If it was something like lack of competency/awareness (eg, 'we didn't understand what the Standard meant') then OK, put that down, but do address that cause because it will trip you up elsewhere.
The corrective action is clear: set measurable objectives, and
use them. They say where you want to go, what you want to achieve. There's a whole heap of threads here with information about objectives here if you search.