Which video format will I get, and what do I do with it?

Depending on your browser, you'll get either an MP4 or a WebM file. Instagram and TikTok work best with MP4. Current versions of Chrome, Edge and Safari usually produce MP4. If you get WebM, convert the video to MP4 with a free converter before uploading it. If you use Chrome or Edge on a computer, it usually works right away.