Hi Diana-- In addition to what Vincent noted, it's also possible to upload a PDF/file to the Sugar Market Asset Library and simply insert a link to download that file within the copy of the email or through a button.
It's not necessarily an attachment to the email and is instead treated like a link, but it's a bit simpler to set up than dedicating an entire landing page to one download if you don't want to dedicate time/resources to go that route. I would just caution that you may want to clearly mark the CTA as a download for clarity: i.e. "Download the Report" vs. "View the Report" etc.
We do not have the option to put an attachment in a bulk email as it Vincent mentioned, it can cause a lot of negative affects on sending domains and spam scores. Instead, the best practice is what Rose Vickerman mentioned, a link within the email or to a form to download. Either of these work!
