Yes! If there’s some content you’ve written that you want to share, but that doesn’t have a fitting question yet, then you can ask the question yourself and then post your answer to it. Similarly, if you ask a genuine question but later find the answer to it by yourself, you can simply answer your own question. (Don’t simply hide your question, because it might help other people!)
Note that you cannot gain 20 points from selecting your own answer to your own question; but even so, we expect you to be fair in allocating the best answer. If somebody else posts a better answer to the question that you made, then you should award that person the ‘best answer’.
If it becomes apparent that you’re only answering your own questions to farm up-votes, then we’ll probably ask you to stop. In particular, please don’t post a whole bunch of answers to your own questions at once; we want to keep questions where the author doesn’t know the answer toward the top of navigation.