How do I send an email from within LO writer?

I am using Windows10 and GMail. I have looked at setting up using
Tools → Options → Internet
but there is nothing for email

The whole question seems unclear to me, since your usage of the phrase “GMail” is unclear. Since there is no such thing like a Gmail - Client (in the sense there is an Outlook, Thunderbird etc. client), which could be called by another application, you should specify what you precisely mean, when stating “I am using … Gmail”. Do you mean.

  1. I have an account on GMail and use a web browser to send/manage my emails ? — or –
  2. I use my GMail account credentials in another email program (Outlook, Thunderbird, …) to connect to my GMail account and to manage my emails.

It appears that LO makes the assumption that your Microsoft Outlook is already setup to send and receive emails through your Gmail email account. So with that in place, you just click on File → Send → and pick your email file preferences. Then LO will open up Microsoft Outlook with the document ready to send.

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