Hi,
In that case, you'll have to go through a mass action with an action "display the results":
monosnap.com/file/tJUEObSgumGdx9YKA1KL1myjRDloAd
When you process it, you'll be able to edit the values by clicking on them:
monosnap.com/file/Yz7RS9ki6xIDMQNMLGYj1fQKj8agFo
Note that the system generates the invoice number based on the invoice id. And the invoice id is automatically incremented based on the maximum value of the invoice id in the other orders. So potentially, if you want the next invoice numbers to after at a certain number, you could just modify the invoice id of a previous order (even a test order) so that the next order would directly have the correct invoice id and invoice number.