You can now use an eSIM with the Samsung Galaxy Note 20 Ultra if you're a T-Mobile subscriber. The carrier has rolled out an update for the model that adds eSIM support to the phone, allowing you to use your number without having to slot in a physical SIM. It could be very useful if you have two lines, or if you're traveling and need the physical slot for an international SIM. Even though the technology has been around for quite a while, it still not as commonly used as physical SIMs in the US, since very few phones support it.
According to XDA Developers, the Galaxy Note 20 Ultra is the first Samsung phone in North America to offer eSIM capability thanks to this update. In the US, the only other options that allow you to ditch physical SIMs are iPhones and Google's Pixel phones. There are many other models, such as the Galaxy S21, that can technically use digital SIMs, but carriers must enable the feature first before subscribers can use it.
T-Mobile first switched on eSIM support for the iPhone in 2018 and has enabled the feature for Pixel devices since then. If you haven't activated an eSIM for your number yet, check out T—Mobile's support page for instructions you can follow.