Follow the steps to understand the Thunderbird Migration tool
Download, install and run the Thunderbird Migrator, & Read all Important Instructions.
Separate option to Convert Emails / Convert Contacts & Calendars. If you have Thunderbird Profile Configured in your system & wants to migrate its data, choose 'Convert Configured Thunderbird Mailboxes data'. Or you can also add files manually by Click on ‘Select Folder’ or ‘Select Files’ option & browse the Thunderbird folders/files.
Select All or only Required Thunderbird Mailbox Folders in the application panel.
Click on 'Next' button, that will provide list of 20+ Saving Options. Choose Desired file format from the list of Select Saving options.
Click on Folder icon to change the destination path.
Choose the folder from here, or you can also create a New folder directly.
Once You have completed the Thunderbird migration options, click on Next button to initialize conversion. Preview the Live Conversion process in spftware panel.
After Conversion finished successfully, it will display a confirmation message box. Click on OK button to proceed further.
Check your Output files directly from destination location.