To be more polite in English, we add the word "please" onto our requests. In Chinese, the word 请 () serves the same purpose.
In its most simple form, a polite request can consist of only two words.
Obviously, those requests may be significantly longer.
The phrase 请问 () is a set expression meaning not "please ask," but rather, "may I ask." It frequently comes before asking for directions or other polite requests for information.
You may have noticed that the Chinese themselves do not use 请 () nearly as much as we use the word "please" in English. It's not because Chinese people are rude; it's because the word 请 () feels rather formal in Chinese, and most people don't feel the need to use it with family members, friends, or even co-workers.
Here are some other ways to start make a request to still be polite, but less in a less formal way:
Aside from this "please" usage, the word 请 () has some additional uses not covered here. It can mean "to invite," or "to treat (someone to a meal)," and can even be used as a causative verb. None of those uses are covered here.