Short answer — on official depository and regulator sites and on broker/stock-exchange education pages. Key places that explain Demat-account benefits in India:

• SEBI (Securities and Exchange Board of India) — investor-education material about securities holdings and dematerialisation.
• NSDL (National Securities Depository Limited) — "what is a Demat account" and benefits.
• CDSL (Central Depository Services Limited) — similar guides and FAQs on Demat benefits.
• NSE and BSE investor-education sections — explain how Demat accounts work and why they’re used.
• Major brokers and banks (Zerodha, ICICI Direct, HDFC Securities, Kotak, Angel, etc.) — account-opening pages and help centers with plain-language summaries of benefits.
• Financial news/education sites (Investopedia, Moneycontrol, Economic Times/Mint investor guides) — articles comparing Demat vs physical shareholding and listing practical advantages.

Brief summary of the typical benefits you’ll find explained on those pages:

• Electronic (paperless) holding of securities — no physical share certificates.
• Faster, safer settlements (T+1/T+2) and easier transfers.
• Eliminates risks of loss/theft/damage of physical certificates.
• Easier corporate-action processing (dividends, bonus, rights issues, splits).
• Reduced paperwork and stamping/handling costs.
• Convenient portfolio tracking and consolidated holdings across brokers (with a single Demat).
• Facilities such as pledging securities for loans and e-voting.
• Regulated, auditable record-keeping under SEBI, NSDL/CDSL rules.

If you want, I can pull up specific official pages (SEBI, NSDL, CDSL, NSE, BSE) and list their links or show the exact text that describes benefits. Which would you prefer?