Video: mp4 is most preferable, we encourage you to convert your videos to this format (mkv, mov, m4v, webm, matroska and quicktime are also acceptable).
​Audio: mp3, wav, m4a.
​Photo: jpeg, png.
​Font: ttf, otf, woff, woff2.

There are some other limitations:
​Video duration: min 3 seconds, max 5 minutes.
​Video size: Max 1GB.

Audio duration: min 3 seconds, max 5 minutes.
​Audio size: max 50MB.

Font size: max 20MB.