Hi @GonWild ,
we have added the email customization capability just this week. The deployment finished yesterday so your browser may not yet have picked up the new UI. Can you please check again in a few days? The following documentation should help with how you can customize once it shows up for you: https://learn.microsoft.com/en-us/azure/active-directory/governance/customize-workflow-email
If your company policies allow it, you may also use an in-private browser or clear your cache that will force your browser to pick up the new UI immediately.
Thanks,
Alex