Group 1 - The article emphasizes the importance of filing annual tax returns for individuals who have obtained business income from two or more sources, which must be completed by March 31 of the following year [1] - The process for filing the tax return can be completed in five steps through the Natural Person Electronic Tax Bureau's web portal [1][2][3][4][5][7] - After successful submission, individuals can pay any additional tax owed or apply for a tax refund directly from the confirmation page [8] Group 2 - The article provides a detailed step-by-step guide for individuals to log in to the tax system, select the appropriate tax year, and verify their investment unit information [2][3][4][5] - The system automatically retrieves relevant data from previous submissions, calculates the tax amount, and allows users to make necessary adjustments before final submission [7] - It highlights the importance of ensuring all data is accurate before submitting the tax return to avoid complications [7]