show the categories and the date above the title

What about the author and tags? Do you want them to appear above as well?

No. I just want category, date and title in this order

First, we'd need to move it above the title:

add_action( 'after_setup_theme','tu_move_posted_on' );
function tu_move_posted_on() {
    remove_action( 'generate_after_entry_title', 'generate_post_meta' );
    add_action( 'generate_before_entry_title', 'generate_post_meta' );
    add_filter( 'generate_category_list_output', '__return_false' );
}

Then you'd need to do this:

add_filter( 'generate_post_date_output', 'tu_categories_to_date' );
function tu_categories_to_date( $output ) {
    $categories_list = get_the_category_list( _x( ', ', 'Used between list items, there is a space after the comma.', 'generatepress' ) );
    $categories_list = sprintf( '<span class="cat-links"><span class="screen-reader-text">%1$s </span>%2$s</span>',
        _x( 'Categories', 'Used before category names.', 'generatepress' ),
        $categories_list
    );

    return $categories_list . $output;
}

Great Tom !! thank you very much again!!

You're welcome :)

Hi Tom I just want to move category & tags above title. I have date and author at bottom of post, I can't seem to make this work.

I wonder if you could do something as simple as this:

remove_action( 'generate_after_entry_content', 'generate_footer_meta' );
add_action( 'generate_before_entry_title', 'generate_footer_meta' );

Let me know :)

It works but includes all the meta data, rather than just category and tag, and it doesn't remove the bottom. I'll keep trying.

Let's try this instead then:

add_filter( 'generate_show_categories', '__return_false' );
add_filter( 'generate_show_tags', '__return_false' );

add_action( 'generate_before_entry_title', function() {
    $categories_list = get_the_category_list( _x( ', ', 'Used between list items, there is a space after the comma.', 'generatepress' ) );
    if ( $categories_list ) {
        printf( '<span class="cat-links"><span class="screen-reader-text">%1$s </span>%2$s</span>', // WPCS: XSS ok, sanitization ok.
            esc_html_x( 'Categories', 'Used before category names.', 'generatepress' ),
            $categories_list
        );
    }

    $tags_list = get_the_tag_list( '', _x( ', ', 'Used between list items, there is a space after the comma.', 'generatepress' ) );
    if ( $tags_list ) {
        printf( '<span class="tags-links"><span class="screen-reader-text">%1$s </span>%2$s</span>', // WPCS: XSS ok, sanitization ok.
            esc_html_x( 'Tags', 'Used before tag names.', 'generatepress' ),
            $tags_list
        );
    }
} );