Choose the file you want to paste and click Open.Go to the Edit menu > Insert > Page from File.Select a page thumbnail under which you want to place the next PDF or JPEG file.How to combine JPEG files into one PDF on Mac? Follow the same step: just drag and drop it! Also, there is a bit longer way: Drag and drop another PDF file to the sidebar of an open one, specifically to the thumbnail you wish to place it.Choose Thumbnails in the View menu to display thumbnails of all the pages in the sidebar.
If you want to keep the original PDF file untouched, go to File > Duplicate to create a new file copy. Changes you make in Preview are saved automatically.
