Note:
When submitting data to a URL, it is recommended that you specify an absolute target. Relative targets are interpreted relative to the user environment, which can vary from one user to the next at run time.
These formats initiate server-side processing. The XML Data Package (XDP) option submits the form data and optionally includes other information, such as the form design, annotations, and signatures, that is needed for LiveCycle Forms ES to subsequently render the form at run time. Attachments may be included with XDP files only.
To include a PDF version of the form (including signatures) when it is submitted as an attachment, select PDF (Includes Signatures). Otherwise, a reference to an embedded PDF file is included.
To include one or more <xdp> elements in the XDP source file, select Other. The specified elements must be separated by commas and white space is optional; for example: xci, xslt, sourceset.
See also 

To insert a submit button that sends information to a server