The auditor's report — opinion language, structure, signing.
To form an opinion based on the evaluation of conclusions drawn from audit evidence, and to express that opinion clearly through a written report.
SA 700 sits in the Reporting phase of the audit. The Standards on Auditing are issued by the ICAI Auditing and Assurance Standards Board (AASB) and deemed to be prescribed by the Central Government under Section 143(10) of the Companies Act 2013. Compliance with SAs is mandatory for every audit conducted by a Chartered Accountant in India.
For authoritative text, refer to the ICAI AASB Compendium of Standards on Auditing at icai.org.