Hi Reid,
You can share documents, including PDF, by sharing out a workspace with your customers. Create a workspace and upload the documents to it. Then click the Share button and share it with the people you want to have access to it. They can then either view the PDF documents online or download them. You do not need to download any software to achieve it.
If you want to only share individual files, this is also possible if you add them to your Documents workspace and then share them out from there.