many microwave ovens do emit a beep when you press the "start" button. However, it's important to note that different microwave models from various manufacturers may have different features and settings, and some might allow you to adjust or mute the sound.
Some microwaves have the option to turn off or adjust the volume of the beep through the settings menu. This feature can be particularly useful in settings where a loud beep is not desired, such as in a quiet office or late at night in a residential area.
If you're interested in purchasing a microwave with specific sound settings or looking to disable the beep on your current microwave, I recommend checking the user manual or consulting the manufacturer's website for guidance on how to customize the sound settings for your particular model.