What is the evolutionary role of mutation?

Basically, mutations are malignant manifestations. They arise spontaneously or under the influence of harmful factors such as radiation. Beneficial mutations have arisen through natural selection. When thousands of organisms died out, and only the fittest remained. It took many millions of years. But thanks to beneficial mutations, whole kingdoms and species of living organisms have appeared. Mutations occur in our time with all organisms, as evolution does not stop. But keeping track of them is very difficult.