Hi @rogerroger ,
will this auto archive setting delete all the emails or is there any other way to delete the emails.
Yes. The auto archive setting you shared in the screenshot can delete all mails older than 30 days after running. And as mentioned above by mattewbechtol, according to your setting, AutoArchive will run every 14 days, so if you don't need to delete old mails every 14 days, you can clear the checkbox of "Run AutoArchive every 14 days" afterwards.
Regarding your concern about other ways to delete old mails, from the perspective of Outlook client, you can also create inbox rules with the condition "received in a specific date span" and set the action to “permanently delete it”, then choose to run it now on messages already in the folder.
But the downside is that, you would need to do it on each folders separately. So, personally, I’d suggest just using the AutoArchive setting as you mentioned above.
Moreover, from the perspective of Exchange side, you can consider creating and applying a retention policy to this mailbox so as to automatically delete the old mails. More details, hopefully you can find the document below helpful:
Create a retention policy for Exchange Online
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