Here is all you need to know: "sovereign citizens" are delusional conspiracy theorists and you should not listen to a word they say. Like, seriously, they are right up there with flat-Earthers or the fake-moon-landing people.
There is such a thing as "lawful money", sure. But no you don't need to know about it, and no there's no magic invocation to recite that will prevent you from having to pay income tax.