The WP Engine customer portal can be found here: https://my.wpengine.com
This URL will actually redirect you to another WP Engine login page here: https://identity.wpengine.com/
If you’re looking to instead log into your WordPress website hosted at WP Engine, you can use the Customer Portal to “seemlessly” login to WordPress with one-click, no seperate username and password required. More information on WP Engine Seamless Login.