User form field type
From Joomla! Documentation
The user form field type provides a modal select box of users.
- type (mandatory) must be user.
- name (mandatory) is the unique name of the field. This must match the name of the query results column that contains the values that will be shown to the user in the drop-down list, unless a different name is specified in the value_field attribute.
- label (mandatory) (translatable) is the descriptive title of the field.
- description (optional) (translatable) is text that will be shown as a tooltip when the user moves the mouse over the drop-down box.
Example XML parameter definition:
<field name="title" type="user" label="Select a user" />