Here's how Tor works:

When you send an email through Tor, Tor uses an encryption technique called "onion routing" to randomly generate messages through the network. Send mail. It's a bit like putting a secret letter in a stack of letters. Each node in the network decrypts the message (the open outermost envelope) and then sends the inner encrypted contents (the inner sealed envelope) to its next address. This means that if you look at one node alone, you cannot see the entire content of the message, and the transmission path of the message is difficult to trace.

However, the final message has been delivered. If it's a "Tor Hidden Service" on a server connected directly to the Tor network, there's no problem. However, if you're just using Tor as a proxy to access the networks you frequent, it's a bit more complicated. Because at some point, your traffic needs to pass through a Tor "exit node", which is responsible for delivering your packets to the network.