By default, all fields in your app are shown when viewing an item. This can create unnecessary clutter on an item if a lot of fields are left empty, or if you have fields acting as placeholder values to be used in workflows or calculations. So, in the app template, you have the option to hide certain fields in the app when they are left empty, or to always hide them regardless of whether or not they hold a value.
To use these options, click the dropdown menu to the left of any field in the app template. Select "Hidden if empty" to hide the field when there is no value, or select "Always hidden" to always hide the value. If a field is always hidden, this means it will be hidden in the create, view and edit modes for your items. This option should only be used for fields that act as placeholders in workflows or calculations that don't actually need to be viewed on the item.
If an empty field is hidden and you'd like to add content to it, select the "Show hidden fields" option just above the Files section for the item, or hit "H" on your keyboard to show or hide the fields. Note that this will only reveal fields marked as "Hidden if empty", and will not reveal fields marked as "Always hidden".
Notes on fields that are always hidden: