One of the gaps BBM has over WhatsApp is its ability to send files of any type. But this year, 2016, WhatsApp is now able to send documents through chats. This feature is available as an update for android and iOS platforms with several other features. As of now, users can only send pdf files but don’t worry, the file support is likely to expand in future.
It is to be noted that sharing is possible unless both the user and the recipient’s WhatsApp version has been updated. WhatsApp usually rolls out such features from the server side. Therefore users are encouraged to check their stores for update.
Note: Currently, document sharing is only possible with private chats and not yet in Group chats.