This plugin allows you to upload files to services. It is a Tasker plugin and will NOT work without it.
The Content-Type setting in the settings section indicate the mime type of the file to be uploaded. For example, to upload a text file the content-type setting will be "text/plain".
Note that the default content type in the HTTP header is multipart/form-data and could be overwrite by setting a Content-Type header but is not recommended.