Manual:$wgEnableEmail

Details
Set to true to enable the basic e-mail features: Password reminders, etc. If sending e-mail on your server doesn't work, you might want to disable this.

MediaWiki email is almost certainly not going to work out-of-the-box on Windows servers, and it may require additional configuration on Linux servers. See Manual:$wgSMTP for information on how to configure the sending of email.