A tool for life? (4)

I believe the answer is:

file

I'm a little stuck... Click here to teach me more about this clue!

'a tool' is the definition.
(file is a kind of tool)

'life?' is the wordplay.
'life' can be anagrammed to 'FILE'.
But, I'm not clear how this is indicated.

'for' acts as a link.

Can you help me to learn more?

(Other definitions for file that I've seen before include "Dosssier" , "Cutting tool or line of people" , "Tool to hold documents" , "Line on board" , "(Set of) documents- line" .)

I've seen this clue in the Evening Standard.

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