Manual Technique to Migrate MBOX File to Outlook
This method can be applied by using Thunderbird and MS Outlook. Both the application must be installed on the same system.
Convert MBOX to PST
Launch Mozilla Thunderbird then open the folder that you want to migrate.
Use Ctrl + A shortcut then select all the emails of that folder.
Make a Right-Click on the selected folders and Select Save As option.
Browse the location where you want to save the file then Click on Save.
Once all the files are saved Close Mozilla Thunderbird and Open MS Outlook.
Now, create a New Folder and Rename it.
Drag the files which you have saved earlier into the New Folder.
Save the folder in PST file format.
You have successfully saved the MBOX file in PST format. Now it is the time to export that PST file in Office 365 and ultimately convert MBOX to Office 365.
Export PST File to Office 365
Download and Install Azure AzCopy on your System.
Create a Copy of SAS URL.
Now Upload the PST file that you have created.
Open all the emails of the PST file.
Import PST file in Exchange online and then create a new mapping of PST data file. Learn about different Microsoft 365 migration in detail.
I hope this information will be helpful!