Start delivering goods in German city (7)
I believe the answer is:
trigger
'start' is the definition.
(I've seen this before)
'goods in german city' is the wordplay.
'goods' becomes 'gg' (I've seen this in other clues).
'in' indicates putting letters inside.
'german city' becomes 'trier' (I've seen this before).
'gg' going into 'trier' is 'TRIGGER'.
'delivering' acts as a link.
(Other definitions for trigger that I've seen before include "Gun firing device" , "prompt" , "Cause (device) to operate" , "Component of gun" , "make things happen" .)