It enables a writer to get rid of unwanted characters (6)
I believe the answer is:
eraser
'it enables a writer' is the definition.
The definition suggests a singular noun which matches the answer.
'get rid of unwanted characters' is the wordplay.
'get rid of' becomes 'erase' (to erase something is to get rid of or remove it).
'unwanted characters' becomes 'r' (I can't justify this - if you can you should give a lot more credence to this answer).
'erase'+'r'='ERASER'
'to' is the link.
Can you help me to learn more?
(Other definitions for eraser that I've seen before include "Rubber for removing marks" , "What a poor artist needs" , "A student's rubber, or the one who uses it" , "Piece of rubber for deleting pencil marks" , "Stationery item" .)