I am using the ESW support for kmain. I configure with oauth2 for exchange. I test the connection and all is fine and the receiving account is created. From other posts it seems a sending account should be created but none is. Any hints on how to set up to send?

Please include the version of KMail you are using (under Help -> About KMail)

For setting up the Sending account, you should be able to just use a regular SMTP account and set the server to the host name of your exchange instance (smtp.office365.com if you are using office365) with otherwise default/expected settings.