Aha! That message means there isn't an email program installed on your computer, or if there is an email program installed on your computer, you haven't designated it as your default email program.
If you're using an online service like Outlook.com or GMail, that's not a program that you install on your computer. That's a service that's installed on the web.
If you do have an email program installed on your computer, like Office Outlook or Mozilla Thunderbird, you have to tell Windows that it's your default email program.
In addition, we don't know what word processor you have and if it needs additional steps to setup email capability.
Personally, I don't send email from my word processor (Word 365) and here's why: I would rather save my file first, and then mail the saved file. That way, if anything goes wrong during the email process, I haven't lost my work.