You can easily attach calendar invites to your emails as .ics files when sending your email, but we currently don't allow for other file types to be included. We recommend including that information in the body of your email or hyperlinking to a download link.
Why? Sometimes email attachments like PDFs and Zip files can trigger spam filters, and we wouldn't want that important information getting lost in the email vortex. We want your emails to hit the inbox every single time.