Is recording a woman's voice considered 'awrah? And does uploading this recording to YouTube—which does not show the woman and is directed at women or both genders—count as speaking to non-mahram men without necessity? And is it permissible for a woman to speak in a way that makes people laugh about the topics she is discussing, and is this among the jests that should be avoided?

The voice of a woman is not considered 'awrah (something that must be concealed) according to the more preponderant opinion. However, she is prohibited from softening her voice, out of fear of temptation (fitnah). If she adheres to the Sharia guidelines, there is no harm in recording and broadcasting her materials if they are beneficial. There is also no harm in women or non-mahram men listening to them, as long as the causes of fitnah are absent. This does not fall under a woman directly conversing with non-mahram men. There is no harm in mentioning something humorous, provided it does not contain anything forbidden like lying, though it is preferable to avoid it. This does not fall under a woman joking with non-mahram men.