Register WP REST API route

register_wp_rest_api_route.php

<?php

add_action( 'rest_api_init', 'wpc_register_wp_api_endpoints' );

function wpc_register_wp_api_endpoints() {
	register_rest_route( 'somename', '/search', array(
        'methods' => 'GET',
        'callback' => 'wpc_somename_search_callback',
    ));
}

function wpc_somename_search_callback( $request_data ) {
	
}