• Every registered taxpayer under GST is required to file three tax statements each month called GSTR-1 (for sales), GSTR-2 (for purchases) and GSTR-3(consolidated).
• File GSTR-1 between 1st and 10th of the following month. Your sales data from GSTR-1 will populate the GSTR-2A of your customer.
• If your sales records match with their purchase records, they can just accept their GSTR-2A and file GSTR-2 (for purchases).
• Mismatches can be corrected by them before they file GSTR-2 and whenever this happens, the GSTN sends you an alert.
• Cross-verify changes made by your customer and file the GSTR-1A before 17th of the following month to make necessary corrections to your GSTR-1.
• Files GSTR-1 into the GSTN and this data populates your GSTR-2A form.
• Verify data on your GSTR-2A and make corrections, if needed before filing your purchase data in the form of GSTR-2 between 11th and 15th of the following month.
• Pay the tax you owe to the government based on your tax liability before filing GSTR-3 between 15th and 20th of the following month.

Here is a list of all the returns to be filed as prescribed under the GST Law along with the due dates.

Return Form	Particulars	Frequency	Due Date
GSTR-1	Details of outward supplies of taxable goods and/or services affected	Monthly	11th* of the next month with effect from October 2018 *Previously, the due date was 10th
GSTR-2 Suspended	Details of inward supplies of taxable goods and/or services affected claiming the input tax credit.	Monthly	15th of the next month
GSTR-3 Suspended	Monthly return on the basis of finalization of details of outward supplies and inward supplies along with the payment of tax.	Monthly	20th of the next month
GSTR-3B	Simple Return in which summary of outward supplies along with Input Tax Credit is declared and payment of tax is affected by taxpayer	Monthly	20th of the next month
GSTR-4	Return for a taxpayer registered under the composition levy	Quarterly	18th of the month succeeding quarter
GSTR-5	Return for a Non-Resident foreign taxable person	Monthly	20th of the next month
GSTR-6	Return for an Input Service Distributor	Monthly	13th of the next month
GSTR-7	Return for authorities deducting tax at source.	Monthly	10th of the next month
GSTR-8	Details of supplies effected through e-commerce operator and the amount of tax collected	Monthly	10th of the next month
GSTR-9	Annual Return for a Normal Taxpayer	Annually	31st December of next financial year*
GSTR-9A	Annual Return a taxpayer registered under the composition levy anytime during the year	Annually	31st December of next financial year*
GSTR-10	Final Return	Once, when GST Registration is cancelled or surrendered	Within three months of the date of cancellation or date of cancellation order, whichever is later.
GSTR-11	Details of inward supplies to be furnished by a person having UIN and claiming a refund	Monthly	28th of the month following the month for which statement is filed