Use Outlook Reactions to Respond to Emails

All versions of Outlook available in Office 365 can use Outlook reactions to respond to email instead of sending traditional message replies.

M365 Changelog: Outlook - Reactions to Email Messages - Petri IT Knowledgebase

why in my organization no one can see outlook reactions anymore? - Microsoft Q&A

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Introducing 'Reactions' in Microsoft Outlook - ramsac Ltd

Reactions in Microsoft Outlook - Microsoft Support

New: Outlook – Reactions and new notification experience - Super Simple 365

New: Outlook – Reactions and new notification experience - Super Simple 365

Reply to an E-mail Message - Hardware, Software, and Systems

How to Use Reactions in Microsoft Outlook