Group 1 - Individual businesses using the accounting method can deduct 40% of mixed personal and business expenses when calculating personal income tax [2] - Actual wages paid to employees are deductible for individual businesses, but the owner's salary is not deductible [3] - Social insurance contributions made for employees are deductible, while contributions for the owner are limited to 5% of the local average salary [4][5] Group 2 - When issuing invoices for construction services, the location and project name must be specified in the remarks section [6] - For real estate rentals, the detailed address must be included in the invoice remarks [7] - When selling real estate, the property name and address should be clearly stated on the invoice [8]