WordPress.org

You can install this plugin directly from your WordPress dashboard:

1. Go to the Plugins menu and click Add New.
2. Search for Global Post Password.
3. Click Install Now next to the Global Post Password plugin.
4. Activate the plugin.
5. Visit the 'Settings -> Global Post Password' menu and set a global post password.

Now whenever you write or edit a post or page you'll be able to switch password protection on or off with one click, instead of having to manually type in a password for each post. You can change the password whenever you like from the 'Settings -> Global Post Password' menu.

For manual installation, see the guide to Manually Installing Plugins.