Problem with invoice date and number

I’m wondering, when is the invoice generated? Does it happen automatically when the order is marked as complete, or is it generated only after we click the invoice button from the order?

Our free plugin creates a PDF invoice automatically based on the order email notifications attachments, which you can configure under WooCommerce > PDF Invoices > Documents > Invoice > General > Attach to: The attachment process will create an invoice document with its respective number:

For instance, if you have the “Processing order” or/and “Completed order” options selected, when the order has reached the Processing or Completed statuses, the invoice should be attached in its respective notification.

However, even if you do not have any option selected in the “Attach to” setting, you would be still able to create an invoice manually, using the document buttons in the order list, or the order details screen, unless you have disabled the document altogether, selecting the order statuses in which you do not want to create an invoice yet.

You can do this within the “Disable for” option, which is located in the PDF invoices settings as well:

Thanks for providing more details, @sarispi:

Please note that the invoice numbers and date are assigned based on when the document is generated, and this does not always match the sequence in which orders arrive (unless you generate an invoice at order creation, regardless of whether you have received payment or not, e.g. by sending the document to the administrator).

For instance, let’s say that your next invoice number is I-101 and you only generate an invoice when the order changes to Completed status (that in fact appear to be your case). If you receive three orders in a row, with the order numbers 100, 101 and 102, but the order status changes to Completed in a difference sequence: 102, 100, 101, the invoice numbers would look like this:

Order: 100 = Invoice: I-102 (second to change to Completed)
Order: 101 = Invoice: I-103 (third to change to Completed)
Order: 102 = Invoice: I-101 (first to change to Completed)

This is completely normal, but if you are using the order date, instead of the invoice date (which is the default date and the one we recommend), it can produce the issue you have described.

To illustrate this better, and following with the previous example, let’s say that the order and invoices were created the following dates:

• Order: 100 was placed on January 1st = Invoice: I-102 created on January 5th
• Order: 101 was placed on January 2nd = Invoice: I-103 created on January 6th
• Order: 102 was placed on January 3rd = Invoice: I-101 created on January 4th

If you are using the order date, the number sequence and date of the documents would be like this:

• Invoice: I-101 – Document date: January 3rd
• Invoice: I-102 – Document date: January 1st
• Invoice: I-103 – Document date: January 2nd

But if you use the invoice date instead, the number sequence and date would be this way:

• Invoice: I-101 – Document date: January 4th
• Invoice: I-102 – Document date: January 5th
• Invoice: I-103 – Document date: January 6th

Hope it makes sense! 😉