This  document explains how to search for an Outlook .pst file and then add it to  your Outlook profile. An Outlook .pst file is a file stored on your local  computer containing email messages, calendar items and contacts that you have  chosen to store offline. 
  To  search for the .pst file, follow these steps: 
- To  search for the .pst files: 
    
- On Windows 10, click Start, and the search for "This PC", and then click on This PC.
 - Locate the search field on the top right corner.
 
 - Type *.pst in the Search field, and then press <Enter>.
 - Locate the desired .pst file you want to add to Outlook. Record the location of the .pst file.
 - Close  the search window and start Outlook.
In Outlook 2021:- Click on the File tab and select Open & Export.
 - Click on Open Outlook Data File.
 - Navigate to the location of the desired .pst file that you found during your search above. Select the .pst file and click Open.
 
 - Outlook will now display the .pst folder in the Outlook folder list in the left side menu tree.
 
Note: If you want to remove a PST file from Outlook, right click on the PST Folder name in the Outlook Folder List on the left side. In Outlook 2021, select Close <foldername>from the menu that appears. This will remove the PST from Outlook but will not delete it from your system. You can re-add it again later using the instructions above.