Since you are using the sales module, check out the module "Club SO lines" by intelliversal integrated solutions. This module groups the products written under a section with marked checkbox and shows them as a single product to the customer in their invoice.

You manually set the scheduled delivery date in the tab Other in the sales order. Might be an alternativ.

Hi Doug,

the Odoo standard always sets the order date to the time of confirmation of the offer - in order to be able to adjust the order date manually, a small adjustment of the source code is necessary.

In addition, there are already ready-made modules within the Odoo app store that address this issue (e.g. https://apps.odoo.com/apps/modules/17.0/edit_order_date).

Edit: maybe you have a third option - using Odoo Studio 
If you activate Odoo Studio and are on a sales order, you have the option in the upper right corner to go to the higher-level editing mode of the view - there you can select the field with the order date and remove the tick at ‘Readonly’ on the left side - when you leave the mode again, you can then edit the order date and set it to any date you want.

Kind regards,
Chris Dominiak (Intero Technologies GmbH)

 @  Doug,  please   Open the Sales Order: Go to the sales order you want to edit.

Click Edit: Look for an "Edit" or "Modify" button in the sales order form.

Change the Order Date: Locate the order date field and adjust it to the desired date.

Save the Changes: Click "Save" to apply the new order date.