Using len() function we can get the total number of elements in a list. So in a zero based index system ( first element position is 0 ) we can add the element at last position by using len().
append() adds the element at the end of the list ( always) , by using insert we can add element at any given position. If we add element by using insert at the end of the list , then it is same as append().
my_list=['Alex','Ronald','John']
#my_list.append('new name') # adds at the end of the list
my_list.insert(len(my_list),'new name') # adds at the end of the list
print(my_list)