After researching on the web I mentioned below the two free methods to convert MBOX to PST.

Using Mozilla Thunderbird

• Install Thunderbird and add the ImportExportTools NG add-on.
• Import MBOX File: Right-click Local Folders > ImportExportTools NG > Import MBOX file.
• Convert to EML: Select emails, right-click, and choose Save As > EML format.
• Move to Outlook: Open Microsoft Outlook and drag EML files into a folder.
• Export as PST: Go to File > Open & Export > Import/Export, select Export to a file > PST, and save.

Drawbacks

• Complexity of steps
• Risk of data loss
• Time-Consuming process
• Required proper technical expertise

The above method may be useful when you have a small amount of data but when you have a large amount of important this technique does not work appropriately. So, In his situation, you can utilize an expert tool like GainTools MBOX to PST Converter Software. This expert program smoothly converts large amounts of MBOX files into Outlook PST format in just a few quick steps. Also, this application is useful for both technical and nontechnical users. However, these program-connected PST files are easily accessible in any version of MS Outlook 2021, 2019, 2016, 2013, and older ones. Furthermore, this utility is compatible with all editions of the Windows Operating System.

1. Install and Run the Software
2. Browse and add the MBOX files
3. Take a complete preview of Mbox data
4. Choose the PST file format
5. Select the desired location and start the conversion processes