I have just installed OS Catalina and iTunes and my bluetooth apps have disappeared

Hello Scrub bird,

Thank you for posting in the Apple Support Communities. I understand that some apps, including iTunes, are missing after upgrading to macOS Catalina, and I’d like to share some information with you. 

First, in macOS Catalina, iTunes is replaced with the Apple Music app. Check out the support article below to learn more about where you can find your media:

What happened to iTunes?

On the other hand, if you’re looking for other apps on your Mac, I recommend using Launchpad or Spotlight to locate them:

Use Launchpad to view and open apps on Mac

Search with Spotlight on Mac

I hope this information is useful. Kind regards.

Scrub bird,

Thanks for getting back to us with those additional details. I’m happy to hear that everything is sorted out for you. 

Have a great rest of your day.