What are the 3 USPS sevices for the company? -

I m working on a project

Your question is really too vague for an accurate answer. There are many Mailer Services, not just three. Are you looking for services for sending? Receiving? Confirming? Insuring?I will assume you mean for mailing. There is Express Mail, Priority Mail, First Class Mail, Standard Mail and Package Services Mail. Each of these have different standards and requirements.Of course there are also International options that you may also consider.The Domestic Mail Manual and International Mail Manual are available online and can answer your questions fully. It is available at http://pe.usps.gov.