To import MBOX files into Gmail, utilize the Advik MBOX converter. This tool allows for bulk conversion of MBOX file formats and supports all of them. MBOX files can be saved to PDF, PST, MSG, EML, and other formats. Exporting the MBOX files to different email clients, such as you can import MBOX to Gmail, Thunderbird, AOL, etc., is also helpful. Throughout the conversion process, the MBOX converter tool keeps the original folder hierarchy intact and doesn't modify any data.