Get Moodle from the official website, http://www.moodle.org/. Go to the Moodle downloads page and select the version and format that you need.
Installation step 3 – Getting and unpacking Moodle
Choosing a Moodle version
For a new installation, the latest stable branch is usually your best choice. The last build information tells you when it was last updated with a bug fix or a patch. This is usually irrelevant to you; the version number determines which features you get, not the build time.
For a production server, do not use the standalone packages mentioned earlier. They are insecure, because they are meant for use by a Moodle developer for experimentation and development. To make the development of a site easier...