I use Foxmail to handle email in my company, now I'm back in school for a few days and I need to get a few emails that I sent in company. But I didn't see these options in Foxmail or Thunderbird, any suggestions?
The ideal solution is to have an IMAP server for your company, and an IMAP server for your school and for both to be accessible through a remote Internet connection, either directly or through a VPN. You cannot create such a situation if youy only have control of the POP/IMAP client such as FoxMail or Thunderbird.
What many email clients do allow is that you can save a copy of sent emails locally (for example to your notebook/laptop hard disk) and save a copy of received emails there too ("offline working")
In the worst case you can use your email client to forward all received emails to a private account accessible from all locations. Use BCC to also send it a copy of all outgoing messages. This is quite a lot of effort though. Explore your email client's "offline" capabilities.