Only if you know something the public doesn't that could move the needle on the stock price. You don't need to be an officer in the company but generally those are the people who know those critical details.

However if you are told by people in the company about some secret new product, how much the company is loosing (and its not public), have access to financial reports or other such things it could be insider trading.

Generally you should receive training about this subject by the company.