For fundamental information about a public company such as it's history, major products and services, and financial and employee data, try the resources listed below. Start by finding out the company's stock ticker symbol and use that symbol in your search for better accuracy.
Company research often also involves doing research on the industries in which the companies you are interested in are associated.
Analyst reports take much of the research data you are gathering and use it to take a snapshot of where the company stands and what the author of the report believes are the company's future prospects.
Business Source Elite (see link below) has thousands of in-depth analyst reports. From the homepage, click on the More link at the top of the page and select Company Profiles. Then search by company name.