You have to pretend you know how to seduce, to deal with your daughter crying with no apparent reason, to pay taxes because that what adults do.
The point is that if you were trained in your domain, you can't hold yourself up as an example of "an imposter who had to learn it all themselves" because some of it was given to you as "absolute" knowledge. That you weren't "trained" in some 'basic tasks' (and some people are - imagine the boy scouts, preparatory schools or the military) doesn't mean you had to "imposter" your way into learning everything else - you simply learned those "by osmosis". (Otherwise, we'd have thousands of different ways of accomplishing each of those basic tasks in use.)
Social interactions are informed by past interactions, in a sort of "telephone game" through time and society (which is why trends evolve and change). And we aren't trained how to do taxes because there's an entire industry devoted to profiting off them which lobbies to keep it feeling complex and against just having the IRS send you a form to sign or dispute.
But if it's false, why is the imposter story so persistent? Probably because it's relatable. Everyone likes to feel empowered, and it's quite empowering to feel like you could do just as well as a specialist, if only you put your mind to it. And maybe you can. But are you willing to put in the years of work?
On one hand, the Dunning-Kruger effect reminds us that the most competent people tend to question their own capabilities. On the other hand, a lack of confidence is a severe penalty in most areas of your life. The best path is probably to realize whether or not you're trained (or have experience), and if you're trained, don't feel like an imposter. If you're not, don't be afraid to try, but be aware of how far your boundaries can be pushed.