The built-in Mail app in Windows 11 is the default email app on a Windows PC. If you have installed other email app, such as Mozilla Thunderbird, Blue Mail, eM Client, Mailbird, Mailspring, on your PC and would like to send emails using the new desktop email client, you can follow below steps to change the default email client in Windows 11. Note that besides desktop email clients, web-based email applications such as Gmail, Microsoft Office365 Outlook, etc. can also be configured as your default email application.
Steps to change default e-mail client in Windows 11
Click the Windows Start menu, choose Settings > Apps > Default apps. Scroll down until you see Email. Click on it, you will see options to set default file types or link types, including .eml, .wdseml, MAILTO, MID, OUTLOOKMAIL, MS-UNISTORE-EMAIL, etc. Click MAILTO and set the new default email app. By doing this you’ve tweaked the app that will open when you click on any “mailto:” links.
Change default email service in Browsers
Normally web browsers, like Firefox, Chrome, use your operating system’s default mail program to send an email message. You can however set different mail client used by these browsers to overwrite the system or global setting. For example, you can set Chrome to use Gmail, set Firefox to use Thunderbird, set operating system’s email program to Windows Mail, etc.