"Should" is placed at the beginning to make the sentence interrogative. "You should" is an assertion whereas "Should you?" is a question. There is another use for "should you" that is not interrogative. For example, in "Should you have any queries, just ask me for help." in which "should you" means the same as "if". However, in your three sentences that cannot be what is happening because "If you have any queries" is a subordinate clause, not a sentence.

Simply because there are questions. If you say "You should have female friends" instead of "Should you have.." then that's no longer a question.

Hello, Khalil. I am in good health, thank you! And you? "I'm here should you have any queries" is a very polite/formal way of saying "I'm here if you have any queries," meaning "You can come to me if you have questions." The other two sentences sound like a request for advice or an opinion: "Should you have female friends?" means "Is it a good idea to have female friends?" It's the same for the YouTube channels question. I hope that helps, and I'm here should you have any further queries 😉

Imagine you're trying to ask someone for their thoughts or opinions about something, or you're giving them an option to do something. You might use the word "should" at the beginning of the question to make it sound more polite or thoughtful. Here's what those questions mean: "Should you have any queries?": This is like asking, "If you have any questions, please let me know." It's a polite way to say that you're there to help if someone has questions. "Should you have female friends?": This question is asking for someone's opinion about having female friends. It's like saying, "Do you think it's a good idea to have female friends?" "Should you have multiple YouTube channels?": This one is asking for advice or thoughts about having more than one YouTube channel. It's like asking, "Do you think it's a good idea to have more than one YouTube channel?" So, when you see "should" at the beginning of a question like this, think of it as a polite way to ask for someone's thoughts or to offer help. It's like opening a door and saying, "You can come in if you want to." It makes the question sound kind and thoughtful.