Write one's name in the designated place (4)
I believe the answer is:
sign
'write one's name' is the definition.
'sign' can be an answer for 'write' (signing is a kind of writing). I am not certain of the 'one's name' bit.
'in the designated place' is the wordplay.
'in' indicates a hidden word.
'SIGN' can be found hidden inside 'designated place'.
Can you help me to learn more?
(Other definitions for sign that I've seen before include "Communicate silently" , "Traffic control - to write one's name" , "Omen or indication" , "Show" , "Augury" .)