This article explains how you can create and send an electronic invoice (UBL) in Billit in three easy steps (B2C, B2B and Government services).
Please note that you can only remove the last unsent invoice after creating it by clicking the 'Delete' button. It is in fact mandatory to make your invoice numbers follow one another.
If you still want to remove a created invoice after creating several other invoices, you need to create a credit note for that invoice. Otherwise the created invoice can't be matched in the accounts.