acespritech

Are you looking for a way to create an upload form that automatically sends WordPress file uploads to your Dropbox? Using this Plugin you can easily integrate your Dropbox to your WordPress website. You can select maximum file size till your dropbox maximum upload size.
Features:- 
1 – Easy to connect form with Dropbox. 
2 – There is no file limit for upload. 
2 – Admin have short-code of form to display form in any page using it.
Shortcode:- [aspl_dropbox]

ASPL Dropbox File Upload

Another Best Plugin for Integrate Dropbox With Your Upload Form.

Jay Swadas

Add-on plugin for Contact Form 7 – adds the option to upload file directly on dropbox. 
NOTE: This plugin requires Contact Form 7 version 4.8 or later.
<h3>Usage</h3>
Simply go to your form settings, choose the “Dropbox Settings” tab and set the Dropbox access token, file input ID and dropbox folder name.

Contact Form 7 Dropbox

Thanks for this add-on solution. It helped me a lot to fulfil my requirement of file upload with Contact Form.

Easy file upload from Dropbox with Contact Form 7

A simple add-on for Contact Form 7 upload file on dropbox.

ASPL Dropbox File Upload vs Contact Form 7 Dropbox