>>429017I don't know if you're trolling...
Just in case, RAR and PDF are different types of file. RAR is an archive file format (compressed - not always, but usually). PDF is a document format.
Your RARs might contain PDFs, so the way to "convert" them would be to extract the PDFs using WinRAR or 7zip. 7zip is free, WinRAR is shareware.
Or unrar, if you're using some form of Linux, which I don't suppose you are.
You can then delete the RAR files, once the contents have been extracted.