There are two names for a package. The first name is the official name, which is an identifier that you register the package with. The second name is the user-facing display name that appears in the Unity Editor.
Keep the display name brief, yet informative enough so that users can tell what it contains. The Unity Package Manager doesn’t impose any restrictions on the display name.
The official name must conform to the following guidelines and restrictions:
com.example or net.example. This restriction applies even if your company or website name begins with a digit. Following this naming convention prevents name collisions between packages from separate companies.com.unity at the beginning of your own package names.unity anywhere in your package name.
Note: These naming restrictions apply only to the package names themselves and don’t need to match the namespace in your code. For example, you can use Project3dBase as a namespace in a package called net.example.3d.base.