Can't search for Apple Music on my Mac

For me a decision was: iTunes - Preferences - Restrictions - delete check mark on Apple Music

The search choice is contextual in iTunes:

If Show Apple Music Features is on in Preferences, then

• If Library is selected in the tabs on top, then the choice is between Library and Apple Music.
• If For You is selected in the tabs on top, then the choice is between Library and Apple Music.
• If Browse is selected in the tabs on top, then the choice is between Library and Apple Music.
• If Radio is selected in the tabs on top, then the choice is between Library and Apple Music.
• If Store is selected in the tabs on top, then the choice is between Library and Store.

If you are not logged in to your account, then

• If Library is selected in the tabs on top, then the choice is between Library and Store.
• If Radio is selected in the tabs on top, then the choice is between Library and Radio.

Thank you for the screen shot.

Check that you meet the requirements for Apple Music on your computer:

• Internet connection;
• Regions for Apple Music;
• Mac (latest version macOS, but at least 10.9.5) or PC (Windows, at least Windows 7) with iTunes;
• Latest version of iTunes (12.9 if you can; at least 12.2);
• Logged in to the iTunes Store region that matches the region for your Apple ID.

If all that is in order and it still doesn’t work, then it may be time for some macOS troubleshooting:

• Completely shut down. Start up again. Did it change?
• Log out and log in again of your account in the application. Did it change?
• Isolating issues in macOS - Apple Support
• Use safe mode to isolate issues with your Mac - Apple Support
• Try of a different (or new) user account. If it behaves differently, then the cause is something in the user space, probably a settings file. If it behaves the same, then the application itself or the OS may be faulty and should be re-installed. Log in to the regular user afterwards. How to test an issue in another user account on your Mac - Apple Support