WP E-Signature requires many seen and unseen components to magically send/sync your signed documents to third party applications like Dropbox. One of these components is PHP Curl.
Think of curl as the telephone that WP E-Signature uses to place a call to your Dropbox Account. 🙂
PHP Curl (also known as libcurl) is a library on your server that allows WP E-Signature to connect and communicate to many different types of servers and protocols.
We are using curl specifically for syncing PDF’s to Dropbox and for getting temporary remote files within the plugin folders, to generate your beautiful PDF’s.
To learn more about installing and enabling PHP curl, you can checkout the following URL: