Hi @FIX MY LIVE ACCOUNT FINALLY AFTER 5 MONTHS ,
As I know, in the point of Outlook, we actually couldn't add the option on the left of "Forward" as you mentioned, I have the researched a lot for your requirement and found a similar thread , which mentioned you could try to replace the whole reading pane with your own form via Outlook Form Region, please kindly check if it could be helpful to you.
If that’s invalid or you still need more information about the develpoment in Outlook, due to here we mainly focus on general issues about Outlook desktop client, in order to solve your issues better, I added the development tag, thanks for your understanding and hope your issue would be resolved soon.
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