There is no Play Store download, and you do not need one. Add YTMP3 to your home screen from Chrome and it behaves like a native app: its own icon, one-tap launch, full-screen. Thirty seconds, no store, no APK, no permissions.
Tap the icon anytime: it opens straight to the converter, no browser chrome in the way.
Anyone offering a "YTMP3 APK" download is not us. See is YTMP3 safe for why sideloaded converter apps are a risk.
Share a YouTube link straight to the app: in the YouTube app tap Share, copy the link, open YTMP3 from your home screen, paste, convert. For the full Android walkthrough see YTMP3 for Android.
No, and you don't need one. Add the site to your home screen from Chrome and it behaves like a native app with one-tap launch.
Yes. It is a bookmark with an icon: it installs nothing and requests no permissions. Safer than sideloading an APK from a random site.