Thanks for reaching out to the Microsoft Q&A forum.
I wanted to inform you that, unfortunately, by design, Outlook currently does not support adding a follow-up flag while composing a new email. This functionality is only available after the email has been sent, typically by flagging it from the Sent Items folder.
While composing, you can still mark the message with Priority (High/Low) and Sensitivity (Normal, Personal, Private, Confidential), but these don’t function as follow-up reminders.
That said, Microsoft welcomes feedback and feature suggestions! If you'd like to see this capability added in future updates, you can submit your idea directly through the Outlook app. Here's steps on how to provide feedback: Contact support and provide feedback in new Outlook for Windows - Microsoft Support
We apologize for any inconvenience this may cause and appreciate your understanding. If you have any further questions or need additional assistance, please do not hesitate to contact us.
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