Main body administering company gets input device (8)
I believe the answer is:
keyboard
'device' is the definition.
(keyboard is a kind of device)
'main body' is the wordplay.
'main' becomes 'key'.
'body' becomes 'board' (I can't explain this - if you can you should give a lot more credence to this answer).
'key'+'board'='KEYBOARD'
'administering company gets input' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for keyboard that I've seen before include "(Part of) musical instrument" , "Computer input device" , "facility for writing" , "There are various characters on this" , "Piano or computer device" .)