post-type.php

<?php

/**
 * Register the Testimonial post type 
 *
 */
function be_register_testimonial_post_type() {

	$labels = array(
			'name'               => 'Testimonials',
			'singular_name'      => 'Testimonial',
			'add_new'            => 'Add New',
			'add_new_item'       => 'Add New Testimonial',
			'edit_item'          => 'Edit Testimonial',
			'new_item'           => 'New Testimonial',
			'view_item'          => 'View Testimonial',
			'search_items'       => 'Search Testimonials',
			'not_found'          => 'No Testimonials found',
			'not_found_in_trash' => 'No Testimonials found in Trash',
			'parent_item_colon'  => 'Parent Testimonial:',
			'menu_name'          => 'Testimonials',
		);

		$args = array(
			'labels'              => $labels,
			'hierarchical'        => false,
			'supports'            => array( 'title', 'editor', 'thumbnail' ),
			'public'              => true,
			'show_ui'             => true,
			'show_in_menu'        => true,
			'show_in_nav_menus'   => true,
			'show_in_rest'        => true,
			'publicly_queryable'  => true,
			'exclude_from_search' => false,
			'has_archive'         => true,
			'query_var'           => true,
			'can_export'          => true,
			'rewrite'             => array( 'slug' => 'testimonials', 'with_front' => false ),
			'menu_icon'           => 'dashicons-groups', // https://developer.wordpress.org/resource/dashicons/
		);

		register_post_type( 'testimonial', $args );
}
add_action( 'init', 'be_register_testimonial_post_type' );