There are many different ways water service can be run.
In some climates water meters are above gound. But in most areas they are either in a pit or inside the house for older houses.
If the meter is in a pit then there is a usually a shutoff vavle there.
But in some areas they use a separate "curb" shut off, specially if the meter is inside.
The curb ***** (aka curb stop or corporation stop) is under a small metal cover abour 3-4" in diameter.
They often require a special handle to operated. They are a long rod with a U shaped fitting on the end to go over the valve. Ihave seen them at places like HD and Lowes for about $20
In some areas the meter and/curb ***** require special tools to open the lids.
In some cases the city will have to shut off the water. But some plumbers have a unit that will freeze the pipe and cut off the water when it is dificult find/operate the shutoff valve.
There should be a whole house shutoff immediately where the water enters the house. And that is usally the part of the house/basement/crawlspace that is nearest the water main connection. But in a few case there aren't any.
The you have to determine how the toilet stop valve is attached to the pipe. Most common are thread, compression fitting, or soldered.
I would suggest calling a plumber to do this and install a whole house shutoff if you don't have one.