The Crocodoc Plugin allows you to upload pdf, doc/docx, ppt/pptx, png and jpg files from WordPress to Crocodoc and embed them in posts using ShortCode
Yes, you need a unique Crocodoc API key, which you can obtain for free from here: https://crocodoc.com/
Go to the Crocodoc Setting page ('Settings' >> 'Crocodoc') and select the post types you want Crocodoc to work with. The Crocodoc metabox will only appear on post types of which you select on this screen.
Use the ShortCode [crocodoc] in your post content to display the attached document. Control the size of the document with parameters 'width' and 'height' : [crocodoc width="300" height="500"]
The Crocodoc plugin must send your file to the crocodoc api, which converts your file into html and stores it on a server, then sends a response back to your site, with information the plugin uses to associate the uploaded document to your post. This association cannot be made without waiting for the response from crocodoc.com.
Currently, the plugin only supports attaching one document per post.
You can delete documents from crocodoc by selecting the 'delete from crocodoc' option in the settings page, and then deleting the post the attachment is associated with.