Article 141 mandates that all tax returns must be accompanied by the taxpayer's formal 'accounts' for the relevant period. These accounts include the balance sheet, profit and loss account, and all supplementary notes and schedules. Crucially, the Law requires that these financial statements must be audited by a legally licensed auditor in Oman. This requirement ensures the reliability of the financial data used for tax assessments and aligns Oman's tax practices with international standards of corporate transparency and financial oversight, particularly for entities of significant size or complex structure.