Hi Nitin,
The model reflection module will be your best option.
https://appstore.home.mendix.com/link/app/69/Mendix/Mx-Model-reflection
Add the module to your project, go to the "MxObjects" snippet and add the export to excel button to the members datagrid. Then run your project, go to the model reflection page, synchronize, select the entity you want and export all of the members to excel.
Hope this helps!
You can export the documentation by right clicking on your project in the navigation and selecting export documentation.
https://www.mendix.com/blog/my-5-favorite-recently-discovered-visual-modeling-tricks/