How to use sendmail with Laravel?

I have tested a password reset feature on Laravel 5.5 using mailtrap.io.

I use these credentials in the .env file:

MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=**
MAIL_PASSWORD=**
MAIL_ENCRYPTION=null
Auth=PLAIN

It works okay. However, I now need to deploy it to an Ubuntu server which already has a configured sendmail package, but what settings do I need to include in the .env file?

The docs does mention sendmail, but what's an example set of settings?

via Chebli Mohamed