These settings are located under the Features tab of block settings, and here you customize the Title and Subtitle texts and can add a Background Image for the whole block.
By default, there’s only one button, but you can use the Add Button option to add more buttons.
In the Call to action with email capture layout the button allows to capture the user’s email, but in the rest of the layouts it has the following Action options:
Open page to open another page within the app;
Scroll to section to scroll to a specific section within the page;
In this layout, instead of a simple CTA button, you have an email capture area. You can set the button Action to send the captured email to one of the supported services (more details in the Integrations section) or simply forward it to the specified email address.