RLevine

Thank you or replying! Our site was created 6 years ago and we didn't sign off on any upgrades but this changed a couple days ago. Unfortunately there is no option for "Header and footer" in that section. 
We did notice that there was an update to the section 'Printing orders' a couple days ago so perhaps this is related? https://support.squarespace.com/hc/en-us/articles/206540967-Printing-orders

I just heard back from customer care with a better understanding of what happened:
"Thanks so much for getting back to me and for that additional context.

I conversed with my colleagues to try and get to the bottom of what's going on. In the process, I was able to find out that the new Customer Notifications Composer removed the ability to add a custom header to invoices specifically. While the customer notifications are branded, the invoices printed from the Orders panel are not. The link below is to a thread on the Squarespace Forum regarding the same behavior you raised: 

Forum: Adding Logo to an Order Invoice

Thanks to your report, I've filed this change in behavior as a bug for our Engineering & Design teams to investigate. They’ll use this feedback when implementing fixes and improvements in future releases.

Please keep in mind that there are many moving parts we need to address before any changes are made, and we can't guarantee changes to this behavior in the immediate future. That said, all feedback is reviewed and your continued input is always encouraged.

For more context too, the removal of the logo in Order Invoices was meant to address a bug where it wasn't possible to delete the customizations once a site was migrated to the new Customer Notifications Composer However, by removing the header, the engineers learned that their is a need for customization for the printed invoice view too. They're on the case already and looking for what they can do.  

I really appreciate you reaching out. If you come across any other unusual behavior in the future, please let me know."