This is embarrassing that you guys (QB Support) haven't added this feature yet. This was first raised as lacking in 2019 in this thread with many customers sharing that they have the same issue and you guys have done nothing?

I have 100+ customers with 100+ invoices going out each month, most of which have different people cc'd on each (by request).I have to manually update the CC field for each line item every month.  QB Desktop has functionality to save CC'd addresses by customer.  QBO does not.  And your prices continue to go up for the same, buggy product.

@Mark_R @MaryGraceS @JessT -- do something please.