What does an IQ score mean?

People often talk about very high IQ scores, often referred to as genius IQ scores, but what exactly do these numbers mean and how do they stack up? It's not always easy to understand what IQ test scores mean. Most professional tests, like the culture fair intelligence test or the classical intelligence test, don't only give you a specific IQ score, they also mention an IQ range.
https://iqcertificate.org/iq-score