I might be wrong, but I think they are just using the twentyfourteen theme that comes with wordpress.
so if is what plugin they use for submit-app
Theme: Twenty Fourteen
Plugins: Web Submitter, Contact Form 7, kk Star Ratings, Simplified Social Sharing, WP Lightbox 2, Font Awesome Icons, WP-PageNavi, All in One SEO Pack
that kind of form can be made using tons of form generator plugin.
best will be Gravity form for this.