If you didn’t setup email, you can do so by editing the details in your app.yml file by setting up DISCOURSE_SMTP_USER_NAME and DISCOURSE_SMTP_PASSWORD variables.
IIRC you can disable Discourse ID completely with the enable discourse id setting.
See this section for setting up email:
Enter these values when prompted by
./discourse-setupper the install guide. To change the current email service, run./discourse-setupas well (this will bring the forum offline for a few minutes while it gets rebuilt).Brevo, previously SendInBlue, GDPR — 300 email per day free
SMTP server address? smtp-relay.brevo.com SMTP user name? [SMTP credentials for your domain under [SMTP-Key tab](https://app.brevo.com/settings/keys/smtp)] SMTP password? [SMTP credentials for your domain under [SMTP-Key tab](https://app.brevo.com/settings/keys/smtp)] Port: 587