If your iPhone is not notifying when you receive a text from person whenever you get a text message nor your banner will show up on you locked screen and will not make a sound when you get text on iOS14 or doesn’t light up when you get text then make sure that mute switch is not on and allow notifications messages do not disturb mode and other methods below.
Unmute by pressing side button, tun off Bluetooth and turn on again, turn on allow notification gir messages, tun off do not disturb mode, Reset all settings.