VTEX charges are always made on an in arrears basis.

So, the period considered is always from the first to the last day of a given month, while invoices are issued in the subsequent month.

An invoice is issued on 03/01, referring to "February". It will take into account all orders that got the approved status in the period between 02/01 and 02/28.

If you're charged before your store goes live, note that it relates to the monthly fee of your environment maintenance. This value is charged because even though the store is not in production it is already consuming VTEX structure.