How to redirect to Magento2 Customer Login page from 3rd Party Application/External application.....?

How to redirect to Magento2 Customer Login page from 3rd Party Application/External application. Suppose, when we want to redirect from any application to WordPress site
we write redirect to http://www.wordpress_site.com/wp-login.php

But I want to know, how we can redirect to Magento customer login page because Magento needs referer. which is where I didn’t understand, How can I pass referer from other application.