PDF Studio can append any of the Supported File Types to a PDF. When non-PDF files are selected they will be automatically converted to PDF before being appended to the document. Files can also be appended by dragging files directly onto the Thumbnail Pane directly.
Select Document > Rearrange Pages > Append Document from the menu and choose the file to insert at the end of the current document.
Use the mouse to select thumbnail page(s) from the thumbnail pane and then: