If you are stopped by someone who makes unwanted inquiries about your service animal, you have a few options. You can choose to ignore the person, you can politely tell them that it is not polite to ask personal questions, or you can answer their questions.
If you choose to answer their questions, you can be as brief or as detailed as you like. There are a few things you can do to let people know that your dog is a service dog. You can use ID cards, service dog registration information, certificates, harnesses, tags, or other accessories.
Remember that you are not required to answer any questions that you do not feel comfortable answering, and you can always ask the person to stop asking questions if they are making you uncomfortable.