I want to send a document as an email
You need a real e-mail client for that, like Thunderbird. You can easily have 3 or more e-mail accounts in Thunderbird , even more than one Gmail account.
Make sure that Thunderbird is configured as your default e-mail client, then Libre should be able to find it.
I use Thunderbird and did not realize this is possible. How do we do it? From looking through the menus, I don’t see an obvious way and don’t know what wording to use in searching for an answer.
Oh, I was looking for information in Thunderbird rather than LO. That was silly of me. The information is in the Getting Started and Writer guides. Anyway, thanks!.