Return handwritten document, enclosing ring, as greeting (6)
I believe the answer is:
shalom
'greeting' is the definition.
(I have seen 'Jewish greeting' mean 'shalom' so perhaps 'greeting' could also mean 'shalom')
'return handwritten document enclosing ring' is the wordplay.
I cannot quite understand how this works, but
'ring' could be 'halo' (synonyms) and 'halo' is found in the answer.
This explanation may well be incorrect...
'as' acts as a link.
Can you help me to learn more?
(Other definitions for shalom that I've seen before include "Jewish salutation, meaning "peace"" , "Jewish greeting and blessing" , "Jewish expression of greeting or farewell" , "Hebrew "ciao"" , "Hebrew greeting or farewell" .)