How I Can Hide All "DONE" Entries in Emacs Org-Mode

I would like to be able to switch on & off display of "done" entries in org-mode.

Alternative - is it possible to open only not-done entries

How do I use Emacs Orgmode?

Emacs does not actually understand you are editing an Org document, yet. To enable Org mode on your current document, type M-x org-mode which will enable the Org mode on the current document. Those are minuses, not underscores.

Is org mode built in Emacs?

Emacs has included Org Mode as a major mode by default since 2006. Bastien Guerry is the current maintainer, in cooperation with an active development community. Since its success in Emacs, some other systems now provide functions to work with org files.

C-c / t (org-show-todo-tree) will redisplay the current document as a sparse tree which only shows TODO items. Alternatively, to show only DONE items, you can use C-c / T DONE.

For more details on sparse trees, see the Org manual.