Why not
Streaming services and video sites deliver music under their own terms, and often protect it with copy protection (DRM). Jam doesn’t connect to these services, and doesn’t remove or work around copy protection.
What you can add
Jam works with audio and video files on your device: see supported files and limits. Only add recordings you have the right to use; the Terms of Service explain your responsibilities.
Songs shared with you
If someone shares a Jam session with you, you don’t need the file at all: open their link and choose Save to keep a copy in your library (shared sessions).