Use rich Interpreter specifications:

The Interpreter head is optional, but useful to specify options or other arguments to Interpreter:

A list can be used to create a menu:

An entity list can be used as a menu:

Choices can be any expression:

A list of rules allows for label specification:

Specify a default for a field; fields that have a default are not required:

Fields can be optional without having a default:

Use RuleDelayed to evaluate a new default every time:

Create a form with input inside:

Input can be delayed:

Change the label for a field:

You can use RuleDelayed and return any expression:

Use None to remove the label:

Change the default label to be something different from the key:

Labels can be any expression:

Change the appearance of single fields:

Use RuleDelayed to evaluate an expression in the cloud:

Use non-rule elements to change the default appearance:

Different types have different controllers. Color pickers for "Color":

Or file pickers for file formats:

Checkboxes for "Boolean":

Change the default controller:

Multiple choices support various types of controllers:

Labels for radio buttons can be anything you want:

The control specification also accepts pure functions:

For strings that are interpreted from natural language in the Wolfram Cloud, sometimes results might be ambiguous:

Disambiguation is off for most types by default, but it can be easily activated:

Sometimes several parts of the expression are ambiguous:

Parts of forms that contain TemplateSlot are not evaluated until the keys mentioned in TemplateSlot[key] are bound to a proper value:

Write a custom title and description:

Use an image for branding:

Use an "ItemLayout" to change form fields' appearance:

Change the submit label:

A pure function can be specified to give a specific layout to a form:

Deploy a form with a white theme:

Deploy a form with a blue theme:

Deploy a form with a black theme:

Deploy a form with a red theme: