Is there a FTP plug in for Jira/Confluence cloud version to enable us to upload the latest version of the document automatically?

[Nic Brough -Adaptavist-]

Generally, you'd use the REST interface to interact with the applications.  Confluence additionally supports WebDAV which allows you to directly create/edit pages as documents.

FTP wouldn't handle documents though, the best it could do is offer to attach files, and you might as well do that with REST.  And ftp is pretty much deprecated and blocked nowadays as it's utterly insecure.

Oh, and you're on Cloud, and an ftp interface would require a type-2 addon, which you can't install on Cloud.