What is "supply decisions"?

Answer 1

Decisions made regarding sources of supply. First, you need to decide whether you want to make a certain item yourself or buy it from someone else. If you decide to buy, you need to decide from whom.

Answer 2

In economics jargon, it usually means decisions by producers about what quantities of outputs to supply (that is, to produce and sell).

Answer 3

depends on the context.

I take it to mean a decision on who supplies or what is supplied, from a companies perspective. i.e. for a baked bean mft - which can mft supplies you or which bean producer etc.