The "Confirm Signature" function is only available during the reporting period, and signature confirmation and signature revocation support a variety of operations. If the taxpayer needs declare in advance deduction due to cancellation of tax registration, he can use the "cancellation check" function to confirm his signature in advance.

Accordingly, except for applying for cancellation of registration, the reporting period of VAT in February 20 19 is the first half of June 2020, so it should be signed and confirmed in June 2020.

Personal opinion, for reference only.