Set Order Status to Shipped(Completed) when adding tracking information with REST API

set_status_shipped.php

// Add this code to your theme functions.php file or a custom plugin 
function ast_api_create_item_arg_filter( $args ) {
 $args['status_shipped'] = 1;	
 return $args;
}
add_filter( 'ast_api_create_item_arg', 'ast_api_create_item_arg_filter', 10, 1 );