GNU Emacs is free software; this means that everyone is free to use it and free to redistribute it under certain conditions. GNU Emacs is not in the public domain; it is copyrighted and there are restrictions on its distribution, but these restrictions are designed to permit everything that a good cooperating citizen would want to do. What is not allowed is to try to prevent others from further sharing any version of GNU Emacs that they might get from you. The precise conditions are found in the GNU General Public License that comes with Emacs and also appears in this manual1. See Copying.
One way to get a copy of GNU Emacs is from someone else who has it. You need not ask for our permission to do so, or tell anyone else; just copy it. If you have access to the Internet, you can get the latest distribution version of GNU Emacs by anonymous FTP; see https://www.gnu.org/software/emacs on our website for more information.
You may also receive GNU Emacs when you buy a computer. Computer manufacturers are free to distribute copies on the same terms that apply to everyone else. These terms require them to give you the full sources, including whatever changes they may have made, and to permit you to redistribute the GNU Emacs received from them under the usual terms of the General Public License. In other words, the program must be free for you when you get it, not just free for the manufacturer.
If you find GNU Emacs useful, please send a donation to the Free Software Foundation to support our work. Donations to the Free Software Foundation are tax-deductible in the US. If you use GNU Emacs at your workplace, please suggest that the company make a donation. To donate, see https://my.fsf.org/donate/. For other ways in which you can help, see https://www.gnu.org/help/help.html.
We also sell hardcopy versions of this manual and An Introduction to Programming in Emacs Lisp, by Robert J. Chassell. You can visit our online store at https://shop.fsf.org/. The income from sales goes to support the foundation’s purpose: the development of new free software, and improvements to our existing programs including GNU Emacs.
If you need to contact the Free Software Foundation, see https://www.fsf.org/about/contact/, or write to
Free Software Foundation 51 Franklin Street, Fifth Floor Boston, MA 02110-1301 USA
This manual is itself covered by the GNU Free Documentation License. This license is similar in spirit to the General Public License, but is more suitable for documentation. See GNU Free Documentation License.