duskwuff's answer is correct if you have a subscription to the Apple Music or iTunes Match services. An Apple Music subscription gives you access to the entire Apple Music catalogue from any device signed in to your account; iTunes Match only lets you download a copy of the music you've imported into iTunes on your computer.
If you don't subscribe to either ...
Make sure that both devices are logged into your Apple ID. This is mostly automatic on the iPhone, but you may need to log into iTunes on the Mac, using the "Account" menu.
Once you have logged into iTunes, Apple Music will start scanning the music in your iTunes library. Any songs which are available in Apple Music will be added to your iCloud library, and ...
Here’s what works:
Double click on the MP3 file and it will start playing oon iTunes
Click on the 3 dots next to the song title now playing and select upload to iCloud music
Watch the spinning arrow on the right. Click on it showing the progress of the upload
When finished uploading, click on the 3 dots again and choose add to a playlist and you’re done.
The track name is taken from the metadata (or, if there isn't any, from the filename) of the tracks during import. So if after the import you end up with the track number in the title this was already encoded in the file itself.
To remove, either edit each title after the import or pick an appropriate script from Doug's AppleScripts for iTunes.
As a troubleshooting step I would start with booting into Safe Mode to see if the behaviour is replicated there, and also to see if the behaviour continues again afterwards when you've logged back in normally.
Boot into Safe Mode
Follow these steps to boot your Mac into Safe Mode:
Fully shut down your Mac
Restart your Mac
Immediately press the Shift key ...
CDA files are not song files, it's just a shortcut.
It doesn't contain any song information, so you can't convert it to other formats.
You need to import cd into a usable format using iTunes on the computer that owns the disc drive.
Note that macOS sees them as "exec" files just because it does not recognize the file type and does not know what ...