The Bureau of Internal Revenue issued Revenue Memorandum Circular No. 75-2020 last 29 July 2020 giving online sellers until 31 August 2020 within which to register their business activity and/or updates without penalty. The same memorandum circular also allowed online sellers to voluntarily declare their past transactions subject to pertinent taxes and pay the taxes due thereon on or before 31 August 2020 without penalty for late filing and payment. You may read the full text of RMC No. 75-2020 here.