Crucial things sent by one in sales all over the place (10)
I believe the answer is:
essentials
'crucial things' is the definition.
Although both the answer and definition are plural nouns, I cannot see how one could define the other.
'sent by one in sales all over the place' is the wordplay.
'by' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'in' is an insertion indicator.
'all over the place' is an anagram indicator.
'sent'+'i'='senti'
'sales' with letters rearranged gives 'esals'.
'senti' put into 'esals' is 'ESSENTIALS'.
Can you help me to learn more?
(Other definitions for essentials that I've seen before include "necessities" , "Things needed" .)