Hi yuki-richardson,
I have a feeling you may have joined QuickBooks Online after having used QuickBooks Desktop, which does have a setting for sounds when recording transactions. It's a helpful audio indication that what you're doing has indeed been completed.
QuickBooks Online doesn't currently have that same feature. Leave our product development team some feedback about this by going to the Gear icon in the upper right of your account and choosing the Feedback option. These comments are sent to the product development team for consideration in future updates. It's a great way to share with us!
Stop by again if you have more questions. Have a great weekend!