Hi,

This depends on what website you want to upload to and how you want to display the video on that site. Are you referring to uploading to your own site or one of the popular video-hosting sites like YouTube? If it's your own site, do you just want to host the video for download to be replayed by an application on the local computer of your visitors or do you want to embed it as a streaming video via a suitable playing applet? These are all questions that might be relevant in choosing the best output video format.

Generally speaking, you can create a variety of video formats via the export function in the "File" menu of the Magix video programs. For Internet usage, you're always looking for maximum compression to get smaller files and enable people to download or stream the video files properly and quickly, even if they don't have high-end bandwidth connections. Using a format that is very compatible and widespread is also a plus. WMV (Windows Media Video) with one of its low bandwidth presets might be a good idea. As opposed to what the name might suggest, it's also very compatible across the platforms (including Mac). WMV also uploads well to YouTube, alongside e.g. DivX (in an AVI container).

I hope the info above helps to get you started.