yes ,there is a cover on the main line going into the wall remove and you will find a slot for a flat screwdriver to fit in , turn to your right to shut off
Same as a regular toilet.
Medical supply places should have them.
Toilet parts
A loud whistling in the pipe after flushing the toilet may indicate that the shutoff valve needs to be replaced. Replacement valves are available at most home improvement stores.
A frost proof toilet the trap is located below the frost line
It doesnt, trust me.
Holes under toilet bowl rim need cleaned out.
Extra toilet paper.
Shut the water supply off to the toilet. Flush the toilet. Pull the old flapper out and replace it with the same type. Turn the water back on and test the toilet.
Any plumbing supply that sells fixtures
1.5 Inch
It depends what you mean by shut off POPPING OUT? More info needed