How do I use Gmail as my mail server?

If you have a working Gmail account you can use Gmail as your mail server by setting it in the global configuration.

On the server tab set the following:

Mailer: SMTP
SMTP Host: smtp.gmail.com
SMTP Port 465
SMTP Security: SSL/TLS
SMTP Authentication: Yes
Set the next two lines with your information. You need to use an app specific password (ASP), described below.
SMTP Username: your gmail username
SMTP Password: your gmail password
The following are also working combinations:

SMTP Port 587
SMTP Security: STARTTLS
SMTP Port 25
SMTP Security: STARTTLS
The SSL module does not need to be enabled in Apache.

The OpenSSL extension needs to be enabled in PHP. The details can be found at www.php.net/manual/en/openssl.installation.php

If you are using WAMP on Windows, the openssl module is not enabled by default and you need to enable it. To do this:

Open the php.ini file and uncomment the line extension=php_openssl.dll by removing the semicolon ; from the beginning of the line.
Save the php.ini file and restart the Apache service.
Note
Note that if you use 2-step verification in Gmail, you need to add a new password in Settings - Accounts - Change accounts settings - Other Google Account settings - Security - 2-step verification - Manage your application specific passwords.