VAT / GST period closes Video training manual 2019 - Click Here   System Configuration > Administration > Financial periods setup VAT and GST. Closes allows 1 to report on backdated documents that have VAT or GST in them. The report will check for processed documents that have been posted in a closed GST period. When you run the report the back dated transactions will be highlighted in blue. There are three reports, select the report for the VAT / GST period Report.