One who handles the keys in office (6)
I believe the answer is:
typist
'one who handles the keys in office' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is the entire clue.
Can you help me to learn more?
(Other definitions for typist that I've seen before include "Keyboard user" , "Forerunner of the word processor operator" , "Worker taken from pool, perhaps" , "Person at keyboard" , "Someone paid to copy using a keyboard" .)