https://www.theverge.com/2018/3/16/17129358/samsung-galaxy-s9-s8-note-8-bixby-how-to-turn-off-disable

The Galaxy S9 has arrived in the United States and around the world. After unboxing Samsung’s latest flagship phone and fawning over its sleek design (and the inclusion of an actual headphone jack), it probably won’t be long before you find yourself hitting the dedicated Bixby button. If you’re a fan of the assistant and its powerful ability to control apps and change settings, maybe you’ll be doing so intentionally.

But a lot of you will inevitably bring up Bixby when you mean to change the volume; the buttons are a little too close together to avoid the occasional mistake. If you find it happening often, you’ve got the option of disabling Bixby entirely. That way, accidental presses of the button will have no effect. Bixby won’t interrupt what you’re doing, and you won’t have to waste time dismissing it.