You can perform the following steps to export PST from Thunderbird. Install the Mozilla Thunderbird Backup Tool on your machine. Choose your Thunderbird account. In the subsequent wizard, select the files or folders that you want to export. Select the saving format as PST from the drop-down menu. Select the tool’s feature as per requirement. Assign a name and destination for the resultant output. Finally, click on the Convert button and you’ve successfully exported the Thunderbird mailbox to PST.