By default the numbering of your invoices is set to be sequential, as is in compliance with EU law. If, for whatever reason, you would like to change this numbering or would like to reset from a certain point then you can find that information here.
Invoice Number Options
There is two types of invoice numbering options:
Sequential will simply number from one and upwards. This is the default setting and it is recommended that you leave it this way unless you have a good reason to change it. If you would like to switch to the WooCommerce Order Number instead, then you can do this too.
Reset Invoice Counter
If you would like to reset the invoice counter, you may do so as well. Simply select the ‘Reset Invoice Counter’ button and below it, set it to which number should come next.The next invoice generated, in this example, would be invoice number 64.