If you don’t want to migrate MBOX file to Office 365 manually then I would like to suggest MailsDaddy MBOX to Office 365 migration tool. The software is built on simple GUI interface that allows technical and nontechnical both to export MBOX file to Office 365 mailbox.
Steps to transfer MBOX files into the office365 account.
Download the MailsDaddy MBOX to Office 365migrater.
Run this tool and click on the Browse button
Click ADD MBOX files(browse file) >> Hit Next button.
After that, select the folder that you want to migrate into office365.
Then click on Export selected.
A pop-up window appears. Select the Office 365option and Browse the location if you want.
Here you can add a filter if you want to Export by date. Then click Export.
After that, give the Office 365credential like Tenant ID, Client Secret (Value), client ID and User ID
Now hit the Sign in button.
There are two ways in this post. The first method is manual which you will need technical knowledge to use. Whereas the second method is straightforward and user can migrate multiple mailboxes from MBOX file to Office 365 at once. To explore more detail or use free demo version of the software, you can visit official site.