Is it possible to use Civimail without unsubscribe / opt out option?
Yes you can. There is an override option under Admin &gt; CiviMail &gt; CiviMail Component Settings
ie at civicrm/admin/setting/preferences/mailing?reset=1

Disable check for mandatory tokens
Don't check for presence of mandatory tokens (domain address; unsubscribe/opt-out) before sending mailings. WARNING: Mandatory tokens are a safe-guard which facilitate compliance with the US CAN-SPAM Act. They should only be disabled if your organization adopts other mechanisms for compliance or if your organization is not subject to CAN-SPAM.