How to pass a 2d array of strings in C programming?

firstName, lastName and fullName are contiguous areas of memory that get treated as (LEN_NAME x NUM_NAMES) matrices. When you pass them arround the called function needs to know the row length (LEN_NAME) so that when it subscripts by i (fullName[i]) it will do the calculation fullName + (i * LEN_NAME) (here fullName is the address of the start of the memory area) so that it will get to the beginning of the i'th name.

#include <string.h>
#include <stdio.h>
#include <string.h>
#define LEN_NAME 34
#define NUM_NAMES 3
void lowest(int array[], char fullName[][LEN_NAME], int elements);
int main(void)
{
    int scores[NUM_NAMES] = { 230, 330, 423 };
    char firstName[NUM_NAMES][LEN_NAME] = { "john", "james", "mario" };
    char lastName[NUM_NAMES][LEN_NAME] = { "goirgi", "edison", "luca" };
    char fullName[NUM_NAMES][LEN_NAME];
    int i;
    for (i = 0; i < NUM_NAMES; i++) {
        strcpy(fullName[i], firstName[i]);
        strcat(fullName[i], " ");
        strcat(fullName[i], lastName[i]);
        printf("Your scores is %d with your full name is %s.\n", scores[i],
               fullName[i]);
    }

    lowest(scores, fullName, NUM_NAMES);
    return 0;
}

void lowest(int array[], char fullName[][LEN_NAME], int elements)
{
    int i, small = array[0], j = 0;
    for (i = 0; i < elements; i++) {
        if (array[i] < small) {
            small = array[i];
            j = i;
        }
    }
    printf("%s scored %d.\n", fullName[j], small);
}

It's usually more idiomatic to make arrays of pointers to chars for this situation:

char *fullName[NUM_NAMES];
fullName[0] = malloc(LEN_NAME);
// ...

You can either remember their length or put a NULL pointer in the last position. If you do this you'll need to declare lowest as:

void lowest(int array[], char *fullName[], int elements);