Hi auntijoan, I'm not sure Windows is able to direct your document to a browser, or whether Firefox would know that it is intended to be send using Gmail.

What steps are you taking here:

When I type a document or do anything that I would like to mail to someone else directly, Windows 10 says I don't have a default email. (I copy and paste to my email, and send it that way - very cumbersome.)

For content you are working with inside Firefox, you can set Gmail as your default mail program on the Options/Preferences page. This article has the steps: Change the program used to open email links.

Thank you! I went into options/preferences, and Gmail was already listed. I guess this is a problem when I want to "send email" when I'm in Windows Edge. I guess I'm on the wrong help forum?

I think if you are in the Edge browser, or any other browser, then Firefox is going to be ignored.

I was thinking maybe you were using Microsoft Word or another non-browser application that has an email or send button or menu command.