Quoting from [peej]:
My supplier will send his pro forma invoice in the form of a scanned letter. please, what is a scanned letter?
Peej :
The Letter here is the draft of Invoice ( Pro forma) that will be made by supplier for you
as for to let you know how much and many are your order and how it will be proposed
to pay (by You) terms and through what payment and to which account.
Scanned = scan = copy machine of documents , pictures etc that can be connected/filed
directly into your computer and save as a file/picture either ones.
So, the copy of pro forma Invoice will be sent to you via e-mail as attachment.
Is it clear for You ?