I work for my boss.
This is OK grammatically, but feels odd to me because it seems rather tautological: by definition the person you work for is your boss, so there's no need to say so. It would be better to indicate the specific person who is your boss:
- I work for him
- I work for Amanda Jones
- I work for Dr Jenkins
- I work for the CEO (you'd only say this if you report directly to the CEO)
(Of course if you are self-employed, or unemployed, then you wouldn't be talking about working for somebody in the first place.)
I work in a accouting corporation. (usually for business area )
You wouldn't say that you work in a corporation, you'd say at or for them. It is correct to say in when talking about which part of the company you work for, or if you are talking about a place. So:
- I work for an accounting company.
- I work at a famous legal firm.
- I work in the accounting department at Samsung.
- I work in the cafeteria.
- I work in London.
- I work for Samsung in London.
(Also, note that it's an accounting corporation, not a accounting corporation.)
I work at Samsung.
This is correct. It would also be correct to say I work for Samsung.