You can use other free services such as WeTransfer, Dropbox, Google Docs and Share File to upload your files and place a download link in your email. The link can be text, an image or a button.
Campayn has also partnered with Digioh to help you send files in your newsletter. Our integration with Digioh allows you to easily send large trackable files in your newsletter. Digioh will also track which one of your subscribers downloaded your file and will alert you if it gets forwarded. Sign up for a Digioh account here.