You can send all types of files as attachments, including word processing or spreadsheet documents, audio files, image files (.bmp, .jpg., .gif), web pages saved as HTML files, and more. Currently you can send an email of up to 20MB, including up to 10 attachments. (Note that you must use Internet Explorer 5.x or Netscape 4.x to send attachments.)
If you're using the original Yahoo Mail interface, here's how to add an attachment to a message:
Once the files are attached, you can address, compose, and send the message as you normally would. To remove an attachment, click the "Remove" link next to the attachment's file name.