The best way to manage your Gmail emails is to convert them into CSV format. In this regard, I’ve recently explored an informative article that explains the detailed procedure of the manual method to export Gmail emails to CSV.
However, the manual methods have a lot of complications to perform appropriately. In that case, you can also go with an advanced Gmail Backup Tool which is a secure and reliable approach for migrating Gmail emails into several file formats such as CSV, HTML, PST, MBOX, EML, etc. It also facilitates its users to backup their emails with or without attachment files. Moreover, users can also migrate their emails to Office 365, IMAP, Thunderbird, Hotmail, and many other email clients.