The first thing you need to do is connect one of the PST files to Outlook. To achieve this,
Go to the “File” tab in the Outlook and select “Open.”
Now, click “Open Outlook Data file,” and select the file that you want to open.
Now, copy the content from this file and paste it to new Master PST file. You can also use the drag and drop option to copy content from one PST to another.
Once the data is copied to Master PST file, remove the original PST file from your Outlook. You can remove the PST file by:
Go to the “File” tab and select “Account Settings.”
Now, click “Data Files” in the opened window. Select the desired Outlook file and click “Remove.”
This method is a bit complicated for non-technical individuals as it includes a lot of creating and removing pst files. So, you can try merging two PST files with a simpler method.
Hope this information is helpful to you