Hi @Fadia Farhat ,
Thanks for your reply.
According to my research and test, when you switch to the new Outlook, your existing folders will be migrated into categories, and you will see them as categories in the left navigation pane.
An additional article for your reference: https://techcommunity.microsoft.com/t5/microsoft-365-blog/new-improved-contacts-in-outlook-on-the-web/ba-p/3639773/page/2#comments
Classic Outlook:
New Outlook:
If there is any update on this thread, please let me know.
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