It's not possible to have the month names translated, but you can change the date format to one that does not use the full month names, like YYYY-MM-DD.
You can do that by doing the following:
- Login to Order Printer Templates (Shopify admin -> Apps).
- Click the "Customize template" button on your design.
- In the editor, go into the "Options and formats" section.
- Adjust the "Date format" drop-down at the top.
NOTE: The dates added by Store Pickup & Delivery apps are not possible to reformat, as we don't have access to and can't control it from within the template code. The template simply shows the text as provided by the Store Pickup & Delivery apps.