casting - How to use cast and pointers with malloc and sizeof

I am confused about when to use a cast with malloc in C.
What is the difference between these 2 pieces of code (the code in question is the
function that initializes a linked
list):

1st Excerpt:

 struct QueueNode {

            char content;
 struct QueueNode* prev;
 struct QueueNode*
            next;
 };

 struct Queue{

 struct
            QueueNode* first;
 struct QueueNode* last;
};
            

Initialisation of the
Queue:

Queue* queueCreate()
            {
Queue* q = (Queue*) malloc(sizeof(Queue));
q->first =
            NULL;

q->last = NULL;
return
            q;

}

2nd
excerpt:

typedef struct Element
            Element;
struct Element


 {
 int
            number;
 Element *next;

 };

typedef
            struct List List;
struct List
{

 Element
            *first;
};

Initialisation
of the Queue:

List
            *initialisation()
{
List *l = malloc(sizeof(*l));
Element
            *element = malloc(sizeof(*element));


if (l == NULL ||
            element == NULL)
{

            exit(EXIT_FAILURE);
}

element->number =
            0;
element->next = NULL;
l->first =
            element;


return l;


            }

This is what I don't
understand:
why in the first excerpt do we use a cast
(Queue*):

 Queue* q = (Queue*)
            malloc(sizeof(Queue));

while
in the 2nd excerpt, there is no cast but we pass a pointer (*l) to sizeof, and there's
no cast?

Liste *l =
            malloc(sizeof(*l))

So
I guess the problem is when to use the cast and when to pass a pointer to the sizeof
function.

ps. I read some answers here on so
like this one href="https://stackoverflow.com/questions/4519834/using-malloc-and-sizeof-to-create-a-struct-on-the-heap">Using
malloc() and sizeof() to create a struct on the
heap

it's about c++ and it
says you have to add a cast. In C, does the cast depend on the type of
implementation?

Thank you for your
help