In the two-envelope system, a bidder submits the technical bid and the financial bid in two separate envelopes within the same submission. The technical bid contains qualifications, experience, methodology and compliance documents. The financial bid contains only the price.
Evaluation happens in a fixed order. The technical bids are opened and scored first, and only bidders who meet the minimum technical threshold have their financial envelopes opened. This prevents a low price from being considered before technical competence is established.
The practical lesson for bidders is that price is irrelevant if the technical bid fails. Common technical failures include missing signed documents, insufficient experience certificates, and specifications that do not exactly match the tender requirement. The technical bid deserves at least as much attention as the price.