I haven't had time to try this yet. But it might be what you looking for.
https://www.nulledfrm.com/threads/pending-orders-to-prepare-picking-list.9291/
I did not recommend it. If you accually read my post you should be able to understand that my post is a copy & paste of whats new in version 2.6.0.
Take it easy!
This module works fine for me, so try that one
https://www.nulledfrm.com/threads/pdf-invoice-template-delivery-custom-number-module-v1-3-1-latest-by-globo.18839/