You can easily convert mbox emails to PDF, HTML, and other formats by using the single tool -
DataVare MBOX Converter. It exports single or bulk mbox files to multiple file formats such as PST, EML, NSF, MSG, TGZ, HTML, Gmail, O365, etc. It is compatible with all MBOX-supported email clients like Thunderbird, Apple Mail, SeaMonkey, etc. Free demo versions also offer all users the ability to convert a few mbox files to other formats for free.