Which files are allowed and how large can they be?
There is no list of allowed file types. A brochure as a PDF, a registration form in Word, an inventory list in Excel: anything is possible, as long as the file is no larger than 12 MB.
The file is not sent as an attachment with the email. You can save it in Media and create a link to it from a text, button or image. Sending a file as an attachment is not possible, and there is a good reason for this.
Requirements do apply to images that you display in the newsletter itself: these must be GIF, JPG or PNG.