Power to summon persons compels attendance and document production, with refusal or false evidence attracting criminal and statutory consequences. Proper officers under the CGST/SGST Act may summon persons to give evidence or produce documents in inquiries, following civil court procedure under the Code of Civil Procedure; such inquiries are deemed judicial proceeding and summoned persons must attend in person or by authorised representative and produce required documents, with non appearance, failure to produce documents, or false evidence attracting prosecution under IPC provisions and penalties under the CGST/SGST Act while Article 20(3) preserves protection against self incrimination.