The Government e-Marketplace (GeM) and the Central Public Procurement Portal (CPPP) are different channels. Many businesses use both.
GeM
An online marketplace where government buyers purchase listed products and services directly or through bids. Best for standard goods and services you can catalogue.
CPPP and state portals
Where departments publish tenders, especially works and custom requirements. You download documents, prepare a bid and upload it with your DSC.
Where to start
If you sell standard products, start with a GeM seller account. If you do works, services or custom supplies, enrol on CPPP and your state portal first.
This guide is general information, not legal advice. Always follow the conditions in the specific tender document.