It really depends on the period that you are talking about, also depends what army, how big, from what culture. In general if we are talking about long campaigns and not raids that lasted some days, we know that with an army there is always a certain number of people who follow the soldier and create a supply line, creating camps or city's in certain cases. Usually the supply line is monitored by a high officer.

The best example in the ancient times are obviously the Romans and is a part of their success. They had a good sistem of administrator to which every soldier would refer to. The smallest was the contubernium, consisting of 8 man ruled by a commander called decano. 10 contubernia made a centuria, ruled bi a centurion and so on. For every step you will find a commander or a subordinate who was responsabile for the supply distribution.

During the medieval period the things are a bit different. For example Charlemagne accepted in his army only the people who could afford to buy a bow and arrow or a spear whit some armor (even only a helmet) and that could provide to feed themselves for some week, then during the March they would have the permission to raid and look for what they needed.

Approaching to the modern age the armies become more and more professional and organized in every way

I know that is a superficial response, but I think that for every case there should be a book or more to talk about so you should decide, for example, to find out how much the Romans organized it, then maybe the Spartans, then thegermanic tribes and so on. Is too much to put it together here.