Email Applications allow users to send and receive emails, often referred to as an email client.
Email Applications can be locally hosted ( on your computer ) or can be externally hosted via a software as a service such as Gmail.
Examples of email applications
Local Email Client
Thunderbird
https://www.thunderbird.net
Outlook ( Office 365 )
https://www.office.com
Apple Mail
https://www.apple.com
Opera Mail
https://www.opera.com
Hosted Email Client
Gmail
https://mail.google.com
Outlook Live ( Office 365 )
https://outlook.live.com
Yahoo! Mail
https://yahoo.com
Mail.com
https://www.mail.com