Iteration is about running blocks of code repeatedly.
There are two redundant approaches to achieving that.
First, we combine functions that call themselves with conditional statements. This concept is known as recursion and suffices to control the flow of execution in every way we desire. For a beginner, this approach of backward reasoning might not be intuitive, but it turns out to be a handy tool to have in one's toolbox.
Second, the while and for statements are alternative and potentially more intuitive ways to express iteration as they correspond to a forward reasoning. The for statement is syntactic sugar that allows rewriting common occurrences of the while statement concisely. Python provides the break and continue statements as well as an optional else-clause that make working with the for and while statements even more convenient.
Iterables are any concrete data types that support being looped over, for example, with the for statement. The idea behind iterables is an abstract concept that may or may not be implemented by any given concrete data type. For example, both list and range objects can be looped over. The list type is also a container as any given list objects "contains" references to other objects in memory. On the contrary, the range type does not reference any other object but instead creates new int objects "on the fly" (i.e., when being looped over).