Canon EOS Rebel T7i Mode D'emploi De Base page 152

Handy Features
3 Disabling the Beeper
You can prevent the beeper from sounding when focus is achieved,
during self-timer shooting, and during touch operations.
3 Card Reminder
This setting prevents shooting if there is no card in the camera.
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Under the [53] tab, select [Beep], then
press <0>. Select [Disable], then
press <0>.
To silence the beeper only for touch
operations, select [Touch n].
Under the [z1] tab, select [Release
shutter without card], then press
<0>. Select [Disable], then press
<0>.
If there is no card inserted in the camera
and you press the shutter button, "Card"
will be displayed in the viewfinder, and
you cannot release the shutter.