It's quite simple, let me explain through an example below -
I created 2 lists above as list1, list2.
As per question, I created list3 using list(list1, list2) and created list4 using c(list1, list2).
The difference between them is the way they store the lists in the memory, i.e list3 stores copy of list1,2 as the list members.Whereas list4 stores the list elements in single list with all list elements
Hope you understood.