Why is my function to reverse string in c not working?

I am writing some C Code where the user enters the desired string size and then a string which will be reversed then printed (as opposed to being printed in reverse.) I also would like to mention that I don't want to use external libraries, the whole point of this is to be able to do it manually. I used dynamic memory allocation to create a string of a size inputted by the user and called a "Reverse Array" function. Everything works fine until the function is called. My method for reversing the string followed the same principle as reversing a normal array but instead of moving integers around I moved characters around. Can you explain to me what I have done wrong?

My Code:

#include <stdio.h>
#include <stdlib.h>

int RvsArr(char *Str, int end)
{
    int start = 0;
    char tmp;
    while (start < end)
    {
        tmp = Str[start];
        Str[start] = Str[end];
        Str[end] = tmp;
        start++;
        end--;
    }
    printf("%s", Str);
    return 0;
}

int main()
{
    int ArrSz;
    printf("Please enter array size: ");
    scanf("%i", &ArrSz);
    char *Str;
    Str = (char *)malloc(ArrSz * sizeof(char));
    printf("Please enter your string: ");
    scanf("%s", Str);
    RvsArr(Str, ArrSz);
    free(Str);
    return 0;
}

Read more here: https://stackoverflow.com/questions/66275000/why-is-my-function-to-reverse-string-in-c-not-working