Transfer a file from one computer to another (6)
I believe the answer is:
upload
'transfer a file from one computer to another' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for upload that I've seen before include "Transfer a file from one computer to another" , "add data to system" , "Transfer (data) to a large computer" , "Transfer data to a larger computer" , "Transfer from a remote computer to yours" .)