We already know that Samsung is will run an Android 10 beta for Galaxy S10 models in South Korea soon, but that won't be the only place where Samsung's beta will be available.
Samsung has announced the One UI 2 with Android 10 beta for the U.S. and Germany (via TizenHelp). You'll need a Galaxy S10, S10+, or S10e to participate, and in the U.S., your device must be a Sprint, T-Mobile, or unlocked model. The beta will begin "soon".
If you're interested in registering for Samsung's Android 10 beta, you'll be able to do so using the Samsung Members app.
Samsung hasn't officially announced the new features of its One UI 2 update, but leaks have suggested that it'll include Google's new Android 10 gesture navigation system, Quick Settings improvements, and Note 10 features like native screen recording. While you might run into some bugs with this One UI 2 beta, you'll also get to try out the update before the general public. If that sounds worth it to you, then keep an eye on the Samsung Members app.