While viewing your Site Admin, use the left-hand menu to click "WebApps" and expand the sub-menu, clicking on the WebApp you'd like to edit.
To edit the structure of an existing custom WebApp, click on the "Edit structure" button to the left of the "Add new Item" button. Alternatively, click the settings icon next to the WebApp name in the left hand menu.
Edit WebApp Setup:
From here you can edit any of the following:
WebApp Name - Defines the name your WebApp item.
Has Detail View? - Option to create pages for your WebApp
WebApp Slug - Defines the URL that your WebApp item can be found at.
Detail Page Template - Select template for your WebApp
Detail Layout - Select layout for your WebApp
Secure Zones - Items can be made secure - Choose to secure these items, and whether to show these in list or hide.
Custom Fields - Here you can add, edit and remove custom fields to use for your WebApp. (You can edit the Field Names, Field Types, Field Options, and Required Status).
Note: When changing field types you will lose any content in the field if your new field type does not support the previous content type.
Once you have finished editing, you can go ahead and click save.