National Informatics Centre (NIC), Ministry of Electronics & Information Technology, in close association with the Procurement Policy Division, Ministry of Finance, has developed, hosted, and implemented the Central Public Procurement Portal customized to cater to the electronic procurement/ tendering requirements of the Central Government Departments and other organizations.
The CPP Portal has e-publishing and e-procurement modules.
Central Government, State Government and Public Sector Unit’s Tenders get published on the E-procurement site.
Class Three type Digital Signature is needed to participate in those tenders.
Public Sector Units and Government Organizations have their sites too. You have to register your organization or firms to their portal with all details like Company name, Address, PAN, Registered mail id, contact number, etc.