Last updated: 2017-07-25

Source: https://support.freshdesk.com/support/solutions/articles/226261-i-am-not-able-to-add-more-custom-fields-to-the-requester-widget-

The upper limit to number of fields that could be added to the requester widget is 15. So, it would not be currently possible to add more than 15 fields to the Requester Widget.