You have a couple options to accomplish sending multiple documents as a link in an email.  The easiest way to do this would be to provide a shortcut to the folder itself in the email, the person who receives the email would click the link and the folder would open with all the documents in it.  You are also able to add multiple attachments directly to the email, which would look like this:

What you aren’t currently able to do is use a for each loop to iterate through a collection of documents and add them as attachments. But like I mentioned before, use the for each loop to create a folder and put the entries in it, then just provide a link to the folder.