CD Paper/Tyvek Sleeve

The simplest package is a paper envelope. Versions can add a transparent window to the envelope allowing the disc label to be seen. The envelope can also be made out of spunbonded polyethylene (trade-named Tyvek). This is both more durable and less abrasive than paper.
It is also often used in software packages, where the box is labeled promotionally, but the disc comes in a paper sleeve (to cut costs).