GSTR 2A is a purchase-related tax return that is automatically generated for each business by the GST portal . When a seller files his GSTR-1, the information is captured in GSTR 2A. It takes information of goods and/or services which have been purchased in a given month from the seller’s GSTR-1. It is not a return which you have to file on GST portal. It is just a reconciliation statement from which seller can reconcile his purchases.