The Samsung Galaxy S9 comes with the device name of the same name. This is always displayed when you connect your smartphone via Bluetooth or WiFi Direct, for example.
Usually you can see the name of the device most often when connecting to a Bluetooth hands-free car kit. If you want to change this device name to, for example, your first name, then this works as follows in Android:
Change the device name of the Samsung Galaxy S9
1. Open the App menu
2. Scroll down to “Phone info”
3. Tap on "Device name" and then you can assign a new name
4. OK" confirms the new name for your Samsung Galaxy S9
If you now share the Samsung Galaxy S9 via Wi-Fi Direct or Bluetooth, the device will be displayed with the name you have assigned.
This allows you to see immediately which device you want to connect to.