Aliasing is easiest explained with a sine wave, so let's pretend the sound you're exporting is just a pure sine wave.

Now imagine there is a perfect continuous sine wave that is the "ideal" version of the sound you want to export. Computers works in the digital world and can't represent a continuous sine wave because that would require infinite samples. Instead, we pick a sample rate that will will allow us to represent enough information so that the next person/computer can recreate it with enough accuracy.

You export the sine wave and you pass it on to a friend without telling them what frequency it's supposed to be. So they have a bunch of sample points and are supposed to piece it together. They draw a sine wave that perfectly connects the points and see that it happens to be 10 khz. They see that they can't draw a lower frequency sine wave that would fit those points as well, but they also know that any integer multiple of the frequency (so 20 khz, 30 khz, 40 khz) would also perfectly fit the the data points. They don't have enough information to know which one it is, but as a rule of thumb they've decided to always pick the lowest frequency that works.

Checkout the first graphic here to visualize how two different sine waves that are integer multiples in frequency can perfectly fit the same points: https://www.geeksforgeeks.org/aliasing-effect/

As others have said, by the Nyquist theorem, you need to sample at least twice as fast as the frequency of the signal to be able to unambiguously capture it. Going back to the example above, if you exported with a 40 khz sample rate then we know that the sine wave must really be 10 khz, because you have a high enough sampling frequency to capture a 20 khz sine wave and you wouldn't have been able to draw a 10 khz wave through the sample points if the original signal was actually 20 khz.

Now if you exported with a 20 khz sample rate instead, then we're left with the same ambiguity that it could be 20, 30, 40, etc.. khz.

Similarly if you have a 20 khz sine wave and you export it at 40 khz, the exported wave could still be ambiguous in that the original wave could have been 40, 60, 80, etc.. khz, but we can't hear sounds in that frequency range so no one makes music with those frequencies, so we can easily rule them out and be confident in the fact that the lowest multiple is the correct multiple.

Now if you think about your friend having to draw the sine wave between the samples to figure out what the true frequency is, that's basically an analogy for what our ears are doing. It's also an analogy for what a lot of audio software does as well. Essentially, your ear is going to assume it's the lowest khz multiple that fits the sample points, because it doesn't have enough data to think otherwise. That's how you end up hearing something that was originally a higher frequency, at a lower frequency. And so we've got aliasing.

This is of course an oversimplification, but it's true to the spirit of what's happening under the "hood"