It is a common expression used to express a desire or a hope.
Here are some examples:
* Je souhaite bonne chance. (I wish you good luck.)
* Je souhaite un bon voyage. (I wish you a good trip.)
* Je souhaite que tu réussisses. (I wish you success.)
* Je souhaite acheter une nouvelle voiture. (I want to buy a new car.)
It's important to note that "je souhaite" can be a bit more formal than simply saying "I want."