Squeeze it into one’s composition (7)
I believe the answer is:
writing
'one's composition' is the definition.
'writing' can be an answer for 'composition' (synonyms). I am not certain of the 'one's' bit.
'squeeze it into' is the wordplay.
'squeeze' becomes 'wring' (synonyms).
'into' indicates putting letters inside.
'wring' enclosing 'it' is 'WRITING'.
Can you help me to learn more?
(Other definitions for writing that I've seen before include "Penning" , "Producing (a book)" , "Putting words down" , "Literary composition" , "Penmanship" .)