The following commands are available for editing specifically at the category level (for two other category-editing commands, which are extensions of item commands, see Editing Item Headers and Text):
Add a new category to the current todo file and make that category
current (todo-add-category). If called with a prefix argument,
prompt for a file name and add the new category to that file. This
command is similar to using j, but it only accepts category names
that are not the name of an existing category in the file.
Rename the current category (todo-rename-category). If this
category’s file has an archive (see Todo Archive Mode) with a
corresponding category, rename the category there as well.
Move the current category (with all its items) to another todo file
(todo-move-category). If this category’s file has an archive
(see Todo Archive Mode) with a corresponding category, this command
also moves that category to the archive file corresponding to the moved
to todo file; if there is no such archive file, the command creates it
and adds the category.
Delete the current category (todo-delete-category).5 To delete a category that contains items, you
have to confirm your intent; if the category is empty, deletion is
immediate.
Merge the items of one category into another category, delete the first
category and make the second category current
(todo-merge-category). If both the first and second categories
also have archived items (see Todo Archive Mode), merge the former
to the latter. If only the first category has archived items, rename
the archive category to the merged to category. Minibuffer completion
of the name of the category merged to works as with the navigation
command j, and as with that command, passing a prefix argument,
i.e., typing C-u C g, prompts for a file and confines merging to a
category in that file.
This binding is mnemonic for “kill” to parallel the binding k for item deletion, since d is bound to another item editing command (see Done Items).