For the New outlook that i've switched to, I Can't find the setting: When replying to a message that is not in the Inbox, save the reply in the same folder

Hi @Mohamed Mosaad Welcome to our forum! What's the version of your Outlook client (Outlook>About Outlook)?
And have you received any error reports when the issue occurs? According to your description, I have tested on my Outlook client (version as shown in the below figure), the emails sent in new outlook can be sync successfully when I switch back to old outlook, and both on webmail.
And through my research, I found an article which mentioned Outlook for Mac crashes unexpectedly during mail synchronization. For more information, please refer to: Outlook for Mac crashes unexpectedly on startup or during mail synchronization. If it's your case, please check your Outlook client version and upgraded your Outlook to the latest version. If the above is not your case, considering the non-synchronization between different terminals, please try to adjust the synchronization time of IMAP folder to a shorter time (Outlook>Preferences>under Personal Settings, choose Accounts>Choose your IMAP account>Advanced…>switch to Server tab) and restart outlook to check if there're any differences.

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Hi 
Mohamed Mosaad,  

Thank you for reaching out to us on Microsoft Q&A forum.    

Could you please specify the exact Learn Path/Module name/Exercise link where you are encountering this error along with the screenshots for reference.      

Thank you.

Hi VarunTha, I'm not having an error that was shared by anand my issue is: I was using Outlook 365, found a button to switch to the New Outlook. i tried it, look good. but there was an old setting that I was having it which is,
When replying to a message that is not in the Inbox, save the reply in the same folder . I've tried to search on that option to mark it in the new Outlook, but can't find it. Could you guide how to do it please?