Start with a common format
If Google Drive or a connected app says unsupported file type, convert a copy into a more common format first. JPG, PNG, PDF, MP3, and MP4 are safer targets for most everyday workflows.
HEIC and WebP images often work better as JPG. Word documents are often safer as PDF for sharing. M4A audio may need MP3. MOV video may need MP4.
Drive storage and Drive preview are different
A file can be stored in Drive even if Drive preview or another app cannot open it. Convert the file when the goal is previewing, submitting, sharing, or opening it inside a stricter workflow.
Keep the original
Convert a copy, then open the output before deleting the source. Check image quality, document pages, audio duration, video sync, and whether the receiving app accepts the new file.