Dear Morghan Castorena (mcastorena)"),
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
Based on your description, I understand that you have a concern with "Adding [encrypt] text to email Subject/Body to automatically encrypt". I tested and done researches on my end, it appears that current there is no way to add "encrypt" text to email Subject/Body to automatically encrypt for all users.
I suggest that you give Microsoft feedback about your experience by selecting Give feedback right next to the Need help? button at the bottom of every page. You may post this concern again on our Outlook · Community (microsoft.com). Other people may vote for it and make it more visible to the service team so that it may be considered for future upgrades. I'll keep an eye on this and provide you with a private message if I learn anything useful.
Basically, Office 365 Message Encryption requires that you have an Exchange Online or Exchange Online Protection (EOP) subscription and that you’ve set up Azure Rights Management. user may use the Exchange admin center (EAC) with the keyboard and a screen reader to create mail flow rules (also known as transport rules) to enable or disable Microsoft 365 Message Encryption. See Use a screen reader to define rules that encrypt or decrypt email messages in the Exchange admin center (microsoft.com).
Moreover, there is Encrypt button that replaced the Permissions button, and the new Encrypt button contains both encryption options (S/MIME and IRM); The S/MIME option is only visible if you have S/MIME certificate configured in Outlook. For more, refer to Encrypt email messages (microsoft.com).
Thanks for your cooperation and understanding.
Sincerely,
De Paul | Microsoft Community Moderator