PROCEDURES FOR PREPARING ANNUAL FORM A1 WITHHOLDING TAX CERTIFICATES (BPA1) AND FILING ARTICLE 21 INCOME TAX RETURNS USING CORETAX FOR CLIENTS OF EF SINERGY CONSULTANT

Abstract

This study aims to describe the procedures for preparing Annual Form A1 Withholding 
Tax Certificates (BPA1) and filing Article 21 Income Tax Returns using the Coretax 
Administration System for clients of EF Sinergy Consultant. The study employed a descriptive 
qualitative approach, with data collected through direct observation, documentation, and active 
participation during the internship program. The results indicate that Coretax has integrated the 
processes of taxpayer authentication, employee data verification, preparation and issuance of 
Annual Form A1 Withholding Tax Certificates, tax payment, and electronic filing of Article 21 
Income Tax Returns into a single digital platform. Although the implementation of Coretax 
improves administrative efficiency and supports more accurate tax reporting, several 
challenges remain, including system instability, feature updates, and user adaptation to the new 
digital environment. This study provides practical insights into the implementation of Coretax 
in tax consulting services and highlights the importance of continuous system improvement 
and user readiness to support effective and efficient tax administration.