Hey there livio257,
Thanks for reaching out to Apple Support Communities. I understand your having some issues with your iTunes titles and albums covers after moving them over from an older Mac. I’ll be happy to help with this.
You mentioned you moved your files over to an external drive then to your new Mac. You may want to consider using Migration Assistant to copy all your files over. This can often prevent issues like the one you’re reporting from occurring. You can read more about using Migration Assistant here:
How to move your content to a new Mac
If you want to just edit the existing song info in iTunes, you can use the steps from this link to help:
Change song and CD info in iTunes on Mac
For info on how to add and edit the album artwork in iTunes, you can follow the steps from this link:
Add artwork to content in iTunes on Mac
Best wishes.