$args = array( 'paged' => $wp_query->query_vars['paged'], 'post_type' => 'post', 'cat' => 3 ); code example

Example: wp query

<?php 
// The Query
$the_query = new WP_Query( $args );
 
// The Loop
if ( $the_query->have_posts() ) {
    echo '<ul>';
    while ( $the_query->have_posts() ) {
        $the_query->the_post();
        echo '<li>' . get_the_title() . '</li>';
    }
    echo '</ul>';
} else {
    // no posts found
}
/* Restore original Post Data */
wp_reset_postdata();