Exporting AV1, WebM, GIFs and audio from Video by Zaweba
Video by Zaweba exports AV1 with SVT-AV1, WebM with VP9 and Opus, animated GIFs, Windows Media, MPEG-2, and sound alone as MP3, WAV, AIFF, AAC or FLAC.

MP4 is the everyday export, but it isn't the only format people ask for. A website might want WebM, a messaging thread a GIF, an old DVD workflow MPEG-2, and a podcast just the sound. Video by Zaweba covers these as well, so you don't need a second program to convert your finished film.
AV1
AV1 is a modern, efficient video codec: it can give the same picture quality as older codecs in smaller files. Video by Zaweba encodes AV1 using SVT-AV1, a well regarded encoder. It's a good choice when file size matters and the place you're sending the video supports AV1. Encoding AV1 can take longer than older formats, so give it time on long projects.
WebM
WebM is a format built for the web, here using VP9 for the picture and Opus for the sound. Browsers play it directly, which makes it handy for videos embedded on your own website.
GIFs and older formats
GIFs are short, silent, looping animations that play almost anywhere, including places that won't play a video. The export makes GIFs at 640 pixels and 15 frames per second, a sensible balance between smoothness and file size. GIFs get large quickly, so keep them short, a few seconds is ideal, and choose a moment that loops nicely. Remember they have no sound.
Windows Media files suit older Windows systems and some workplace setups. MPEG-2 is the long-established format behind DVDs and some broadcast systems. Neither is the first choice for new work, but when someone needs one, it's good to be able to produce it without a converter.
Sound only
Sometimes the picture isn't needed at all. You can export just the sound as MP3, WAV, AIFF, AAC or FLAC. MP3 and AAC are compact, good for podcasts and sharing. WAV and AIFF are uncompressed, the right choice for handing sound to someone else to work on. FLAC is lossless but smaller than WAV, good for keeping a high quality copy.
Typical uses include turning a filmed talk into a podcast episode, sending the mix to a musician, or saving the soundtrack of a family video. Before you export sound on its own, give the mix a last listen without the picture. Moments that worked because you could see what was happening, a long silent shot or a visual gag, can feel odd as audio only, and a quick trim makes the podcast version tighter.
Picking a format
Start from where the file is going. A social platform will tell you what it accepts. Your own website is happy with WebM or MP4. A chat app might prefer a GIF for a short reaction. Someone finishing the sound wants WAV.
When in doubt, MP4 remains the safest all-rounder, and these other formats are there for when the destination asks for something specific.
A tip for several versions
Many projects end up exported in two or three formats: an MP4 for sharing, a GIF for a teaser, an MP3 of the sound. Video by Zaweba's render queue works through jobs one after another, so you can set them all up and leave them to run.