One of the more powerful areas of CrushFTP is the WebInterface. It allows for simple file transfers for users with only the use of a web browser. All major browsers are supported. You can customize the colors, logos, styles, and with your own custom javascript, you can change virtually any other aspect too. 

It also allows for customized messages and forms to be displayed to the user so that you can request additional details on their first login, or with every file that they upload. The user can be allowed to rename, delete, upload, download, view thumbnails and slideshows, view movies, share files with temporary links, and search the files they have access to. No limits on the file sizes, and the HTML5 transfer mode allows for resuming transfers in the event of a network interruption. The HTML5 transfer mode also allows for compression during the transfer, and bandwidth acceleration over slow high latency connections.

Here is a link to the public demo server where you can experiment with how things work.