Article 74 of the Implementing Regulations of the Value Added Tax Law establishes the rules for obligations due on non-working days. It mandates that VAT returns must be filed and tax payments must be made on or before the prescribed date, irrespective of whether it is a working day. For all other obligations under the Law and Regulations, if the deadline falls on a non-working day (defined as Friday, Saturday, or a state holiday), the obligation is considered fulfilled if completed on the next working day. This provision ensures clarity for taxpayers in meeting compliance deadlines.