Hi,Could anyone tell me whether it's possible to lock submitted vat quarters,so if any late invoices for the submitted will get picked following quarter vat report.

Hey susanna2, 

When you file a return in QuickBooks Online this will automatically lock and no transactions can added to this return. If a transaction is added which is dated within or prior to this return, the transaction will automatically show as an exception against the current open return. If a transaction is deleted which was included within the filed return an exception will be automatically generated to account for the VAT in the open return. 

Thanks