Apple changed many things about computer, finally (6,5)
I believe the answer is:
granny smith
'apple' is the definition.
(Granny Smith is an example)
'changed many things about computer finally' is the wordplay.
'changed' indicates an anagram.
'about' indicates putting letters inside.
'finally' says to take the final letters.
The final letter of 'computer' is 'r'.
'many'+'things'='manythings'
'manythings' is an anagram of 'gannysmith'.
'gannysmith' enclosing 'r' is 'GRANNY SMITH'.
(Other definitions for granny smith that I've seen before include "Hard, green-skinned apple" , "Mrs Anything (anag) - it's green and edible" , "Type of apple" , "Fruit" , "Variety of apple" .)