Thunderbird Email client

I am using Godaddy's email system which can only be used online. Can anyone tell me if Thunderbird can be used offline. Suggestions re other email clients which can be used offline would be very helpful.

Years and years ago I used Outlook Express which I found perfect but I understand that Outlook Express has been discontinued. I loose the internet signal quite a lot so during those periods I can not prepare my emails. Any advice would be useful.

Kind regards
Barrie