A draft red herring prospectus (DRHP) or simply an offer document is the document which a company submits to the market regulator SEBI before listing on the stock markets. The document includes important disclosures about the IPO-bound company such as its business and industry overview, financial statements, growth prospects, risks and even promoters' background. Further, the document also states the purpose of raising the money.
The DRHP has the most authentic and detailed information about the company and hence investors should carefully study it before subscribing to an IPO.