I work in a design company. I am a designer. Is the design I made in the company owned by the company?

You can think of it this way: unless you have a special agreement with the company, everything you create during working hours belongs to the company, because you have been paid for it. But if your design creates great enterprise value, you can apply to the company for 30% of the proceeds as an intellectual property reward. But if you have a special agreement with the company, for example, that you have a special design and create great value, the company can enjoy profits from it, but the copyright belongs to you, that is another matter. I hope I can help you. If you think you will often have these creations, you can ask the company. In order to retain talents, they should agree to your overlord clause.