Thank you @Tut , You’ve understood it correctly.
And what you’ve said it correct (the deference between order and contract). But we only make contracts and do sales or purchase based on that contract amount and quantity. That’s why I’m using the contracts as order. Everything going well, except the title(name) on the forms.
And I’ve seen nearly similar topic here Document(Invoice) name in customer/supplier statement not same as original doc title - #3 by lubos
That’s why I expected this topic too may have the same attention.