Understanding different layouts in Zoho CRM

Understanding different layouts in Zoho CRM

Hello, 

I have a question about the different layouts that are possible to create in the modules. 

Is it possible to create something like an "extended" layout with all available fields and a "reduced" layout with only the most important fields. But are the fields the same in both layouts? 

I ask because in Zapier I can choose the different layouts I want to fill data into with Zapier or other applications. And I do not understand why I can switch the layout there (if the fields are the same). 

Thanks for help, 
M.