How to use element specification in Export ?

Questions
1

Hi!

I want to use Export to write a File where I can specify elements. I have tried many forms, one of them is

Export[NotebookDirectory[] <> 
  "prueba.pdf", {{"Data" {1, 2}}, {"Graphics", 
   Image[Graphics[Disk[]]]}}]

I am afraid I could not deduce the correct syntax from the documentation

Thanks for any help!

Jesus