Once you create a category to organize your apps, you can change its name easily. When you edit the name of a category, all the apps assigned to that category are updated with the new name.
To edit a category:
On My Apps, switch to the list view:
On any app, select the arrow in the Category column, then select Edit.
In the Edit Categories dialog, change the name of one or more categories, then select Ok.
Your edits appear automatically in the category list and on your app list. All the apps assigned to the categories you edited receive the new name.