Shortcodes for custom login form is not available with the plugin , so where to find it.
Thanks for your query.
GS Custom Login has NO shortcode.
Please check the Screenshots (Settings Option) section here https://www.gsamdani.com/product/gs-custom-login
What should I do when GS Custom Login doesn’t work after activating?
Head to GS Custom Login > General settings > Plugin Status. Select ACTIVE from dropdown. When done, click save settings.