Safer classroom formats
PDF is usually safest for documents and worksheets. JPG or PNG works for image uploads. MP3 is easier for audio playback. MP4 is the safest general video format.
When conversion helps
Convert Word documents to PDF when layout matters, phone photos to JPG or PDF when a document is required, and iPhone videos to MP4 when playback or upload fails.
Check the upload
Open the converted file after upload if Classroom gives a preview. Make sure the teacher will see the correct pages, image, recording, or video.