The best way to attach a file for downloading is to create an archive (zip) of the file before uploading it to the server. Folders and complex file formats such as applications and Keynote presentations must be archived before uploading.
To embed a media file such as a graphic, movie, or audio file so that people don't need to download it first, click the Insert Media button instead of the Attach File button.
To create an archive:
In Finder, select the files you want to compress.
Choose File > Compress, or click the Gear button and choose Compress.
To attach a file:
While editing a page, position the insertion point where you'd like the link to the file to appear.
Click the Attach File (paperclip) button.
Click Choose File, select the file, and click Choose.