2 Questions regarding themes and details of business

I have two Questions tried to find a quick answer in threads but was unable to find so creating a new short topic
The Current Plain theme of invoice we are using shows following columns
Code : Description : quantity : Unit price : amount
I just want item name to also appear
Code : Item Name : Description : quantity : Unit price : amount

What code or changing should i make in custom theme template as I’m not a programmer but need a less hassle solution

Secondly is it possible to have separate business details on the sales invoice and purchase invoice
Like the sales invoices show sales department numbers and email and purchase invoice shows purchase department numbers and email etc
And can we have two email addresses for sale and purchase as currently we can only use 1 email address for both but i think purchase orders or invoices should be sent to suppliers by purchase department’s email address

Both are possible with custom themes, though not particularly straightforward. But this isn’t a coding forum. Hire a local programmer if you don’t have the skills personally.