Music Library not showing up in iMovie
Trying to select music for a project and none of my Apple Music downloaded/purchased music is appearing in iMovie. How do I get my catalog of music to appear in iMovie?
MacBook Pro 13″, macOS 11.6
Songs that are purchased from Apple Music cannot be used in iMovie. They won't show up in iMovie. Being a subscription service you are only renting the songs, so to speak, and cannot acquire ownership by downloading them to an app. One's use of the song requires maintaining the subscription. Also, the songs are DRM protected, that cannot be removed by downloading them to iTunes.
Songs purchased from iTunes after year 2009 are not DRM protected and can be used in iMovie. They do have to be downloaded, however. You said that they were "downloaded/purchased", but you should check that. Open your iTunes library from the iTunes website. Any songs with a little cloud icon next to them are not downloaded. Click on them to download, and they should then show up in iMovie.
-- Rich