PDF Converter is the best app to convert your documents to PDFs. With a very simple interface, you can convert to PDFs within seconds and there is no need for any special permissions. You just need to import the file you want to convert and it is ready to go. After you are done, you can choose the destination folder for the PDF files and it will save all the files for you. There are tons of options to choose from and the only thing you need to do is select the file you want to convert to PDF and it is ready to go.

This app is free and works for iOS.