Hello everyone Ron here. Microsoft Outlook offers two file formats, PST and CSV, from which you may easily Import Contacts Into Outlook. However, before you begin importing, you should first study 'How to import contacts into outlook.' PST (Personal Storage Table)- This is a one-of-a-kind file type used to store data in Outlook, Exchange Client, and other Microsoft services. Contacts, on the other hand, are already in the correct format in the .pst file.