I have a few questions about structs and pointers

For this struct:

typedef struct tNode_t {
    char *w;
} tNode;

How come if I want to change/know the value of *w I need to use t.w = "asdfsd" instead of t->w = "asdfasd"?

And I compiled this successfully without having t.w = (char *) malloc(28*sizeof(char)); in my testing code, is there a reason why tt's not needed?

Sample main:

int main()
{
    tNode t;
    char w[] = "abcd";
    //t.word = (char *) malloc(28*sizeof(char));
    t.word = w;
    printf("%s", t.word);
}

Thanks.