Need more info. Can you take pictures manually? Which shooting mode are you trying to use? Indoors or outdoors? Brightly lit scene, or is it dark? Hand held, or on a tripod? Etc.
Describe the conditions as best you can that cause your issue so that someone else can try to reproduce your issue.
By default, the camera uses "One Shot" focus mode - which also uses a feature called "focus priority". In that mode it will not take a photo unless it is able to lock focus.
On the side of your lens, there is an "AF/MF" switch (auto-focus / manual-focus). Switch it to MF and test the camera. Is it able to shoot (nevermind that the shot may be out of focus)?
If it will take the shot when auto-focus is disabled then it indicates the camera or lens is having a focus problem. Most of the time this is due to a problem with the lens and you could confirm this if you had a different lens to test.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.