Yes, you can. Upwork requires that you contract, invoice and receive funds through Upwork with clients you first encountered on Upwork. This is reasonable and helps keep Upwork open and available to all of us. If your client suggests working outside of Upwork, he is cheating Upwork and will probably cheat you, also.
When asked, I usually tell a client that I am happy to have multiple channels of communication with my clients, but I will only work, invoice and collect money through Upwork if that is where we met one another. That is not just a legal requirement of using the site, it's an ethical obligation. In the past fifteen years I've had only two clients object. I did no work for either client.
Upwork might try to discourage you from communicating via private email, but to date it has not prohibited it. It is useful to put a copy of all correspondence with the client in the workroom so that everything is located in one place. It's a good business practice, and UW is then assured that you're being completely open.
Lahiru, it is up to YOU to decide whether or not to share your email address with any client, or prospective client.
If you don't want to spend time thinking about it, or if you want to be cautious, then simply use a throwaway or project-specific email address. Clients certainly do not care whether or not you provide them with your prime email address.
re: "But I'm worring about it affects to banned my upwork eccount."
That simply doesn't happen.
Upwork repeatedly and consistently tells freelancers that they can share their email address with clients.
The Upwork Help documentation tells us that. The Upwork moderators tell us that. In all the time I have been here (6 years) that has never changed.
Upwork doesn't ban anybody for sharing their email address.