To identify a problem in your community, you can read your local newspaper or visit its website. You might also know about a problem related to your school that you can write about.
Your thesis statement should include what the problem is, what people are doing to solve it, and whether that has been effective. For example, wildfires are a big concern on the West Coast of the United States right now. The thesis statement for an essay about wildfire concern would include the extent of the fires and the damage they are causing, as well as what can be done to help fight or prevent them.
You might want to think about dividing your essay into three main parts: background information, what's being done to solve the problem, and what the future holds. When examining any community problem, you first want to start with background information about that problem. For example, the California wildfires were caused in part by years of drought and high summer temperatures. Then, you want to discuss the extent of the problem, including the problem's effects on the community. For example, in the case of wildfires, you would mention the number of acres they have affected, their cost, and the number of people who have died due to wildfires. Then, you would speak about how your community is attempting to handle this problem. Finally, you might discuss what you propose for the future to help solve this problem, or what experts suggest to solve this problem. You would want to aim for about 150-200 words per section so you can come up with an essay of 500 words.