In Multistep the action hook name is displayed in the corresponding tabs. This can be copied and used according to the purpose. The developers can add their own codes in these hooks for adding the content to the corresponding steps.
What is an Action Hook?
In WordPress theme and development, Hooks are functions that can be added in the specific locations in the WordPress file with a tag. The users can hang their own code in these locations by using this specific tag for changing the core functionality of WordPress(Including themes and plugins).