Web
Hover over Settings in the bottom left-side menu and click All Settings
Select Board and Pieces
Toggle off the Play Sound option
Click Save to apply the changes!
Mobile
Tap More in the bottom right and select Settings
From the settings menu tap Board
Toggle off the Sounds option
Mobile Notifications
Android
Go to your phone’s settings and tap on Apps & Notifications
Select the Chess.com app
From here, you can enable or disable notifications for the app:
iOS
Go into your Apple device's settings and tap Notifications
Select the Chess.com app
From here, you can enable or disable move notifications, notification sounds, and badges: