I am looking for an online search page where I can find the EIN for a regular C-corp which was formed in New York.
Any corporation in the USA is operated under state regulations that requires them to submit periodic reports that may include the EIN. If the corporation is publicly traded, the EIN is found on each and every SEC filing it has ever submitted, most of which are public record.
Go to your Secretary of State's website, lookup the business name and view the documents they have filed over the years. Or, if a public corp, go to SEC.gov and look it up there. Or go to the corporate investor's website and find one of their annual reports.
Similarly, many state and federal agencies require disclosure of the corporate EIN for things like government procurement or various benefit programs, all of which are public records.
edit: I just went to sec.gov, typed in a corporate name, clicked on their most recent 10Q (annual report) link and the first page showed their EIN. Similarly, their quarterly 8Ks each show the same number. Took less than 45 seconds.
You cannot. An EIN for a business is like a SSN for a human. Once someone has it they have access to all of your personal information.
Business do not put that stuff on line and they prosecute anyone who tries.
You can't. That information is not readily available. You would have to call the company directly. Why do you need it?
There is no such database or website.
There is no such online database of EIN numbers.