A wax ring is literally a ring of wax that forms a water tight seal between your toilet and the drain pipe (which is called the flange) it is bolted to. Because of the wax ring, water (mixed with the undesirable stuff) reliably goes down the drain, and does not leak out from under your toilet.
However, wax rings do not last forever. It is much cheaper to replace the wax ring on your toilet every two or three years than to have it fail after five or six.
One of our customers owns a rental house where that very failure happened. Rather than paying us to change the wax ring earlier, she paid us to rip up and replace her flooring.
Below is a video that walks you through the process. This is something you can do yourself.
Most of us are proactive about our car maintenance because we know it costs less to keep the car running well than to wait for a major failure. This concept also applies to our homes.
When you need help with tasks like this or larger plumbing issues, please contact us. We have great home repair and home improvement professionals in our network.