If you're not sure if a ceramic bowl is oven safe, there are a few things you can do to test it. First, check the bottom of the bowl for any symbols or markings that indicate it is oven-safe. If there's nothing there, you can try doing a quick Google search of the brand and model of your bowl.
Another way to test if a ceramic bowl is oven safe is to place it in the coldest part of your fridge overnight. In the morning, take the bowl out and put it directly into a preheated oven set to 350F degrees. After an hour, check on the bowl. If it's cracked or broken, then it's not oven safe. However, if it looks unchanged, then it should be fine to use in the oven.
The best way to be 100% sure that your ceramic bowl is oven safe is to buy one that is specifically labeled as such from a kitchenware store