You have two techniques transfer & Export OST to PST File. You can do it manually or by using any third-party Outlook OST to PST Conversion Software available in the online market. Automatically you import one by one mail item in PST Outlook. This ost to pst converter free download tool is long and irritability practice. Now the second way is third-party tools. I advise for using best free unlimited ost to pst converter Tool.
Because Outlook can't directly import from an OST file like it can from a PST file, if you want to copy your offline data to another computer, you can either configure the email client to connect to your server and create a new OST file, or convert your OST content to the PST format.