How can I print multidimensional arrays in C?

Use nested for loops. For example

for ( size_t i = 0; i < 3; i++ )
{
    for ( size_t j = 0; j < 4; j++ )
    {
        printf( "%2d ", number[i][j] );
    }
    putchar( '\n' );
}

Pay attention to that it is a bad idea to use magic numbers like 3 and 4. Instead use named constants.

As for the conversion specifier %s then it is used to output one-dimensional character arrays that contain strings

Here is a demonstrative program

#include <stdio.h>

int main(void) 
{
    enum { M = 3, N = 4 };
    int number[M][N] =
    {
        { 10, 20, 30, 40 },
        { 15, 25, 35, 45 },
        { 47, 48, 49, 50 },
    };

    for ( size_t i = 0; i < M; i++ )
    {
        for ( size_t j = 0; j < N; j++ )
        {
            printf( "%2d ", number[i][j] );
        }
        putchar( '\n' );
    }

    return 0;
}

Its output is

10 20 30 40 
15 25 35 45 
47 48 49 50 

To output a two-dimensional integer array as a one-dimensional integer array apply casting to the array designator to the type int * or const int *.

For example

#include <stdio.h>

int main(void) 
{
    enum { M = 3, N = 4 };
    int number[M][N] =
    {
        { 10, 20, 30, 40 },
        { 15, 25, 35, 45 },
        { 47, 48, 49, 50 },
    };

    const int *p = ( const int * )number;

    for ( size_t i = 0; i < M * N; i++ )
    {
        printf( "%2d ", p[i] );
    }
    putchar( '\n' );

    return 0;
}

The program output is

10 20 30 40 15 25 35 45 47 48 49 50 

And vice versa to print a one dimensional array as a two-dimensional array use the following approach.

#include <stdio.h>

int main(void) 
{
    enum { N = 12 };
    int number[N] = { 10, 20, 30, 40, 15, 25, 35, 45, 47, 48, 49, 50 };

    size_t rows = 3, cols = 4;

    for ( size_t i = 0; i < rows; i++ )
    {
        for ( size_t j = 0; j < cols; j++ )
        {
            printf( "%2d ", number[i * cols + j] );
        }
        putchar( '\n' );
    }           

    return 0;
}

The program output is

10 20 30 40 
15 25 35 45 
47 48 49 50