This module adds an invoice_number field to allow creating series, with token support. If enabled and the order has the field, it will try to generate an invoice number if the order field has autofill checkbox checked, if not checked (must not be checked by defaukt) and there's a value defined, it will use this value. When autofill is checked It will auto fill the value, looking up the last order in the specified series when saving, and increasing by one the last value. It's important to say that it will not check if payment is done. If you want to check if order is payed before updating this field, implement in payment state event_subscriber to update this field whenever is commerce_payment is done instead.