File Upload field
The File Upload field type allows users to upload a file attachment that is stored in this field. The file will be opened in a new browser window when clicked by the user.
You can specify a maximum size for files, from 128KB up to 2MB. In addition, the Advanced Field Properties section allows you to Index this field as part of the text search engine, which automatically indexes files uploaded into this field.
Check Make files publicly accessible if you want the content of uploaded file be accessible without checking for a valid login session and user's access rights. If you upload a different file to a field that is publicly accessible, the URL for that file does not change.
IsPDFAnnotationEnabled field is set to true in the System Console > System > Shared
Properties > General > Add/Remove Features, the Enable PDF
Annotation checkbox assoicated with the File Upload field is
visible to enable the PDF editor function on the PDF files.