This can be accomplished by certain types of PDF software (Rotate Pdf Online , Nitro, probably others). I’m pretty sure that Rotate Pdf Online Reader and most other applications that can open PDFs are not generally capable of this. There do appear to be some open source applications that can edit existing PDFs, but I have never used any of them for that purpose and cannot speak to their effectiveness in this area.
You have two PDFs and the option to add them to a folder.