Mutations do increase information in the sense that it reduces the entropy of a genetic pool. Consider the example of a bunch of molecules in a sealed container. They attain maximum entropy when they all have the same temperature. If one molecule were to become much colder than the rest then the entropy of the molecules would be reduced. In other words, the information content of the molecules when they are all at the same temperature is at a minimum. There is no way to distinguish one molecule from another. But if one molecule is much colder than the rest, we are able to distinguish it and the information content of the collection of molecules has increased. Likewise with mutations. If the mutation makes one individual of a genetic pool distinguishable from the others, then the information content of the pool has increased because of the mutation.