It's hiding in the song menu — easy to miss on mobile because the screens are cramped.
Where to find it: open any song in your library, tap the ... (more options) menu on that song. Mashup lives in there alongside Cover, Extend, and Replace Section. It's per-song, not a big button on the main screen — that's why everyone misses it.
If it's not there:
1. Update the app. Mashup rolled out in stages; an old app version won't show it. Check your app store for updates.
2. Check the website too. If mobile still doesn't show it after updating, suno.com on your phone's browser has the same ... menu and usually gets features first.
3. Feature flags are real. Suno rolls features out to user groups gradually. If a friend has it and you don't, it's not you — it just hasn't reached your account yet. It typically arrives within a week or two.
Quick rule for any 'where is X' question in Suno: it's almost always in the ... menu on a specific song, not on the main navigation.
Good luck! Hank founder of SonorixPG