Currently, the returns cannot be exported because the department does not support XML schema or Excel templates.
You can refer to Form VAT 200 in Tally.ERP 9 and manually enter the values in the department's portal.
Alternatively, you can print Form VAT 200 and fill in the details manually in the department portal using the values from Form VAT 200.
Note: Form VAT 200 can be generated/printed from Tally.ERP 9 from Release 5.2 onwards.