It doesn't necessarily involve lying, or claiming expertise where you don't have it, but instead a keen sense of what you know, and how some of it fits together. More importantly, you have a sense of what you don't know so you don't put your foot in it.
Mars is the 4th planet, not the 5th. The red one. You know planets have different gravity strengths, but you can't quite remember if Mars has more or less, so you don't bring it up.
Dickens is an author, 19th century. Tale of Two Cities, Christmas Carol, not sure about the rest. Certainly not Moby Dick.
That kind of thing.
It's funny how our rich tech overlords - Elon Musk and the gang - just fail at this miserably. And they just keep tweeting it out.
A lot of it's just the normal right wing internet stuff like HITLER WAS A LEFTIST, ACTUALLY, and other assorted bits of nonsense history, but they fill their brains with that stuff instead of anything else.