Better people in education (5)
I believe the answer is:
emend
'better' is the definition.
(emending is a kind of bettering)
'people in education' is the wordplay.
'people' becomes 'men' (man is a kind of person).
'in' indicates putting letters inside.
'education' becomes 'ed' (abbreviation - e.g. sex ed).
'men' put within 'ed' is 'EMEND'.
(Other definitions for emend that I've seen before include "Correct, revise (text)" , "Improve (texts)" , "Alter something written to correct errors" , "Make improvements to (text)" , "do editorial work" .)