A puddle of water on the floor near the toilet can be fixed in several ways. On a hot, humid day, condensation dripping from the cool outside of the tank or bowl could be substantial enough to make a puddle. You can simply live with it or install rigid-foam tank insulation.
A chronic leak probably means a faulty water supply connection, spud gasket, or wax ring. Often you simply need to tighten the hold-down bolts to solve the problem. A crack in a tank can sometimes be patched from the inside with silicone sealant. A cracked bowl should be replaced.