If water is continually flowing into your toilet bowl/pan, there are 3 likely causes:
1) the float on your toilet filler valve has been set too high, so water is reaching your overflow valve and running into the pan
2) If your toilet has a push button (as opposed to a lever), your button may need adjusted so that it is not triggering the flush mechanism
3) there may be dirt or debris under your toilet syphon seal, causing it not to make a water-tight seal
In order to identify the cause of your issue, we recommend taking the lid off your toilet cistern, if possible, then flushing your toilet & watching as the water re-fills in your cistern. If the water doesn't leak into your pan while it is re-filling, this means it is more likely to be your cistern filling with too much water or your toilet button requiring adjustment.
As the water continues to fill your cistern and nears the top, watch to see if your water reaches the top of your overflow pipe (usually a plain white pipe near your syphon). If water fills above this level and starts to drain into your toilet bowl, you simply need to adjust the float on your filler valve so that your cistern fills with slightly less water. If you're unsure how to do this, a quick search online will provide plenty of guides & information on this topic.
Finally, if your cistern has stopped filling up, but no water has trickled into your pan while the lid is off, re-fit your lid and watch to see if water now starts to trickle into your toilet pan. If this happens, you likely need to adjust your toilet flush button. Again, a quick search online will provide guides & information on how to do this.
If you have tried these steps but are still unable to find the cause of water flowing into your pan, we recommend contacting your local plumber for advice.