First you need register a custom post type via functions.php then you have to add WP_Query with your custom post type slug. Here is the example for WP_Query.

<?php
// WP_Query arguments
$args = array(
    'post_type'              => 'post', // slug for custom post type
    'post_status'            => 'publish', // Also support: pending, draft, auto-draft, future, private, inherit, trash, any
    'posts_per_page'         => '5', // use -1 for all post
    'order'                  => 'DESC', // Also support: ASC
    'orderby'                => 'date', // Also support: none, rand, id, title, slug, modified, parent, menu_order, comment_count
);

// The Query
$query = new WP_Query($args);

// The Loop
if ($query->have_posts()) {
    while ($query->have_posts()) {
        $query->the_post();
        // do something
        the_title();
        the_content();        
        the_excerpt();
        the_post_thumbnail();    }
} else {
    // no posts found
    get_template_part('template-parts/content', 'none');

}

// Restore original Post Data
wp_reset_postdata();

If you have a taxonomy in custom post type , then you can add tax_query within the WP_Query.

<?php
// WP_Query arguments
$args = array(
    'post_type'              => 'custom post type slug',
    'post_status'            => 'publish',
    'posts_per_page'         => '5', 
    'order'                  => 'DESC',
    'orderby'                => 'date',
    'tax_query'              => array(
        array(
            'taxonomy'         => 'custom-category', // taxonomy slug
            'terms'            => array(1, 2), // term ids
            'field'            => 'term_id', // Also support: slug, name, term_taxonomy_id
            'operator'         => 'IN', // Also support: slug, name, term_taxonomy_id
            'include_children' => true,
        ),
    ),
);