One possible cause is the main pipe that supply water to the tank is not properly secured. The high water presuure can cause the vibration, hence the noise.

Adjust the stopcock to the water tank half way or less and check whether the noise is still there. This will reduce the flow.

Another possible cause is that the plumber didnt close the cover properly or left it open, hence the noise of flowing water filling up the tank.

The noise should stop once the tank is full. Otherwise there is a leak somewhere and the water from the main will continue to fill the tank.

Check all toilet flushing system to make sure there is no continuous flow of water after a flush.

If the pipe is not properly secured, the vibration can cause a leak again at the joints or elbows after sometime.

Meanwhile, turn the stopcock to medium or low flow.