An audit is compulsory for businesses to verify the accuracy of their financial records and increase investor confidence. There are several types of audits including tax, GST, cost, and secretarial audits. Tax audits are mandatory for proprietorships, partnerships, professionals, and companies with over Rs. 1 crore in annual turnover. GST audits are required for businesses over Rs. 2 crore in annual turnover. Cost audits apply to large companies over certain thresholds. Secretarial audits are needed for listed and large public and private companies. Maintaining accurate records through regular audits can help businesses avoid penalties.