If you want to transfer Thunderbird to Outlook 365 then you will go with this informative article Migrate From Thunderbird To Outlook 365. Here you will get the complete procedure of the manual method to convert Thunderbird to Outlook 365. 

However, the manual method is too technical for non-technical users. So, in that case, you can opt professional solution Mozilla Thunderbird Backup Tool. The tool utility saves your Thunderbird mailbox to PDF, EML, EMLX, JPG, eMSG, CSV, TIFF, JIF, etc. It removes duplicate emails feature protects your mailboxes and saves your space from backing up the identical email. You can try the demo version of the software to analyze the performance. 

Steps to Migrate from Thunderbird to Outlook 365
Download Thunderbird Backup Tool and run it as an administrator.
Select the profile, of whose messages you want to migrate.migrate from thunderbird to outlook 365
Choose the files/folders for migration. In between, you can also preview your added files.migrate from thunderbird to outlook 365
Next, choose the saving format as Office 365 from the drop-down menu.
Enter the O365 credentials such as Office 365 ID and Password.migrate from thunderbird to outlook 365
Manage the utility feature in accordance.migrate from thunderbird to outlook 365
Click the Convert button to export Thunderbird emails to Outlook 365.

Regards,

Rachel Gomez

Download CloudMigration Thunderbird Backup Tool to backup your Thunderbird email in any email client and file format. This tool saves your Thunderbird emails into PST, PDF, EML, MSG, etc. You can migrate Thunderbird to Gmail, AOl, Yahoo, etc. It has a simple GUI Nontechnicle uses this tool very easily. It has some advanced features that make the process easy and safe. You can try its free demo version.

For a straightforward solution to convert Thunderbird files to Outlook PST try the MBOX to PST Converter Tool. You can convert Thunderbird email, attachments, etc. to Outlook PST using this utility. You don't need to install Outlook to convert an MBOX file to PST. Without any issues, this utility completes all of its tasks. There is no data loss, and you may discover a safe and secure version. It will provide you with a complete view of the exported data before conversion. Additionally, it exports bulk Thunderbird files. MS Outlook 2019 is supported, as well as Outlook 2021, 2019, 2016, 2013, and Outlook 2010. Additionally, this application is a professional tool that even non-technical users may utilize. Its operating system is easy to use thanks to its features. Refer:- https://www.sametools.com/convert/mbox/

If you are searching for a reliable solution to export Thunderbird emails to Outlook 365,  I would recommend going through this informative guide. This blog talks about different approaches to perform the migration process. While performing the manual approach, users can face certain limitations.It also talks about the safe and reliable Thunderbird backup Tool that make the migration process easy and smooth. It also provides accurate results in less time span.