Namaste
Sales Order is created when we recieve our Client PO . Order Date is when Sales Order get created .
You are correct , Invoicing can be done next week or month based on shipment to your customer .
Please check below fields
Document Date , Posting Date
Document Date - Symbolizes the date of Sales Invoice submitted to Customer , based on which due date is calculated according to the payment terms
Posting Date is at the time of Sales order for shipment , invoice .
In ideal scenarios Posting DAte & Document Date are same , which you always look into the posted Tables .
Same Sales Order can be shipped , invoiced multiple times with multiple posting Dates under same order date
To control posting date you can do the below setting in sales & Receivables Setup
Set "Default Posting Date" as "No Date" . user can select the date when he will post .
Or Set posting date as Workdate

If you feel I have answered your query , Please verify the answer
Regards
Pallavi Phade