I am using Thunderbird for long time. For storage and other reasons, I want to move my Thunderbird mails to web mails such as Zoho mail. There are some solutions to this issue. You can convert the mbox mails to eml, upload it to web. There is a solution to read this mbox and forward it one by one. Trying all these, I found a easy solution. IMAP come to rescue.
IMAP will sync the folders and mails between client(Thunderbird) and Server(Zoho mail). So, I created IMAP account in Thunderbird, transferred the mails from local folder to Zoho mail folder. Bingo. I can see all the mails in the web interface.
Here is the step by step instructions
1. Download and install Thunderbird
2. Create a Zoho mail IMAP account in Thunderbird. See this link for more info, Configure in Thunderbird
3. Create a folder under the Zoho mail account. Let us say that Test folder.
4. Move/Copy your mails in the local folder to Test folder.
5. Sync the account using get messages.
Now, you can see all your moved mails in web interface.