Emailing doc from LibreOffice writer

My main client for email is google/gmail how can I configure to send any .odt from LibreOffice

Set mail program to work with your Gmail account. Follow instructions for some of popular clients and if your preferred application is not listed there configure it using these connection parameters.

Configure LibreOffice to use your mail client which depends on operating system you run and if that client is currently supported by LO. Look at following answers for more info on that: