Official release of this feature will be rolling out in the next few days, but if you cannot wait and you are concern about your Dropbox security as I do, here are the steps to enable two-step verification beta.
Download and install beta version of Dropbox.
Download link for Mac.
Download link for Windows.
Download link for Linux 64-Bit and 32-Bit.
Sign in to your Dropbox account.
Activate Two-step Verification feature. This link will send you to the Security tab of your account.
In the "Account sign in" section near the bottom of the page, find the new "Two-step verification" option.
Click the "change" link to begin the setup process.
You can select between receiving codes via text message or using Google Authenticator Time-based One-Time Password (TOTP).
Keep the one emergency code safe and handy in case you lost access to your phone.