You can use third party tool like Zimbra to Office 365 Migration tool.
Several features are:
• Quickly transfer Zimbra file to Office 365 account without facing any hassle.
• This software also convert Zimbra files to Office 365 and other file formats such as PST, MBOX, MSG, EML, EMLX, PDF, HTML, etc.
• It extracts all the essential mail data like To, Bcc, Cc, Sent, From, Received, Attachments, etc.
Read More:
https://www.kdetools.com/zimbra/office-365.html
