TL;DR: Apple has updated the mute key on the MacBook Air M4 to feature a speaker symbol with a strikethrough line, replacing the previous design used since 1999. The latter had no strikethrough ...

Touch the sound tile and you should see the mute symbol appear. You can also set up Do Not Disturb modes, but some Do Not Disturb modes can be set to allow calls through, depending on how you set ...