Invoice number equals order number

Yes, you can set this in the plugin settings:

Note that this will only apply to new invoices/invoice numbers, not existing ones.

I have already ticked that checkbbox, however, the order number not correspond with invoice number
look here: https://prnt.sc/u8t6qm

The checkbox was ticket a long time ago, so there’s something wrong

Is this with the default “Simple” template and no additional filters/actions?

This is with Simple default template, I think, nothing was changed there from our side.

And it’s the same inside the PDF?

This is the screenshot of generated invoice: https://prnt.sc/u8tkvbll
Number in yellow doesn’t matter (but it would be good, to be the same as order number)
Number in red needs to be the same as order number.
Here’s the probably code snippet, which is responsible for displaying order number/invoice number

• This reply was modified 4 years, 2 months ago by megosoft. Reason: Please, remove double L at the end of the link, I didn't realize, that there are some private information, what decline privacy policy

Sorry, I forgot to add link to code snippet:
https://prnt.sc/u8uj5o

Thanks for sharing that. You mention that you are using the simple template, but the screenshot in your link to the PDF example shows a layout that is quite different from our standard layout (the Simple template). Are you sure that this is a PDF from the plugin “WooCommerce PDF Invoices & Packing Slips”?

Hello, this is absolutely your plugin, I am sure. However, it seems, that simple template is edited. I have no idea, who have done it.
We need to edit only “Variabilny symbol”, it seems, that it is extra field, please, look again to invoice few messages above
We have in left top column:
– Date of invoice
– Payment
– Variabilny symbol (Variable symbol in english).

However in code, I can’t find that, even with infile search with Total commander. There is something like this:

<?php do_action( 'wpo_wcpdf_after_order_data', $this->type, $this->order ); ?>

I think, that Variabilny symbol field will come from this filter (or what is it). I can’t find, where it is defined. In my current template functions.php is nothing.

I think this means that there are some filters/actions in your theme functions.php (or the Code Snippets plugin or similar) after all, and this may also explain why the invoice number is using a separate sequence. There are no known issues with the invoice number being set to order number. I just double checked again on my end to be sure and it works as expected

Just to be sure you have that Invoice number setting correctly, can you show a screenshot of this?