how to save files in db (word, image files attached in inv.)

Hi

I have three documents that I should attach to an invoice, because these documents are coming with the items.
I wanted to ask if there is any way to attach these documents to the purchase(sale) invoice so they could be stored in the database, so later i can delete these documents from my computer.
These are word, excel or scanned documents.

Please suggest if you have any idea.


Thank you and best regards