Toilets use a wax ring for sealing the toilet to the drain pipe.
Usually a simple repair, shut off the water, flush and drain/wipe water from the bowl, and undo the two/four bolts/nuts holding the toilet to the floor.
Remove the toilet and replace the wax ring.
Check for it leaking anywhere else, tank joint, pipe connection, or cracks in bowl or tank(this is toilet replacement problem).
Most leaks from other places, fill line, gasket joint between toilet and tank, should run along the outside of the bowl.
Make sure the outside of the bowl tank is dry, flush and with a dry hand or paper towel check all around the toilet bowl, especially the back hard to reach places. Should locate where the leak is coming from, a joint gasket or worst case a crack. If bowl stays dry,then the wax gasket needs to be checked and replaced. Wax gaskets are one use only.