The answer to a clogged toilet is to first try plunging the toilet. Use a plunger to forcefully push and pull the water in the toilet bowl to try to dislodge the clog. If plunging doesn't work, you may need to use a plumber's snake or auger to physically break up the clog.
Common causes of a clogged toilet include flushing too much toilet paper, foreign objects being flushed, or a blockage further down the drain line. Symptoms include the toilet bowl not draining properly, water rising in the bowl, or the toilet overflowing when flushed. If plunging and snaking the toilet don't clear the clog, it's best to call a professional plumber as the issue may require more extensive repairs.