Some of the forms allow you to choose between three different types of randomization. If you’re not sure what to choose, you almost certainly want to ‘generate your own personal randomization right now,’ which is the first (and default) option. In this mode, your numbers (or strings or whatever) will be generated based on true randomness created especially for you and which will be discarded immediately after it has been used. There is no way to predict what these numbers will be, and there is no way to recreate the same numbers later. This is the standard way of using a true random number generator.