It would depend on your TV’s OS. Some TVs have different settings and features, and it would be best to check the user manual that came with your smart TV or contact support.
These devices can be used with not only smart TVs, but also other devices like smartphones. They have a 3.5mm input that allows you to plug them into a small headphone jack.
On top of it being a transmitter, it also functions as a receiver. This means you can connect to it via Bluetooth, and it will be able to perform and send audio via the 3.5mm jack instead of receiving it.