There are two modes for filing GSTR-3B using ClearTax: summary mode and invoice import mode. In summary mode, users can directly input tax values. In invoice import mode, users can import sales and purchase books to auto-compute the GSTR-3B summary. For both modes, users upload the data to the government portal, check if any tax is payable, and file the GSTR-3B return. ClearTax also provides reports to compare filed GSTR-3B with GSTR-1 and GSTR-2A. Support is available by email or phone for any queries.