Where is my shutoff valve? Loose key stop

[Dinesh]

Hey folks!
Amateur DIY'er. I'm trying to install an aftermarket toilet water spray (bidet-like). To do this I obviously need to shut off the water to the tank to add the splitter. I can't figure out the darn valve shut off.
I've attached a pic for anyone who can help me out.
Thanks,
Dinesh

 

[Terry]

You missing the key for the stop.
It's called a loose key stop. Normally for commercial settings where you don't want just anybody turning off the shutoff valves.