”Occupation”

Good question!
When you fill in the column "Occupation"
1) you have to put the nature of your work, such as Shipping clerk, nurse, computer sales person etc.
2) If you put on something like: manager, clerk or supervisor etc. it is wrong.

I think it is just a general question being put in some forms.
Only the title is required rather than the position. Say, you are a manager in Food & Beverage Quality Control. I don't think that you have to disclose you job nature while filling these kinds of forms. Just fill in your title - manager. I suppose that no one would ask you which field you are engaged in.
You are not filling the application form for applying a post. Why should you explain so detail about your job?

In my opinion, occupation means job and you just need to fill in your job in present such as doctor, clerk, chef, etc.