How do I handle request bodies with Axios?

Axios supports sending data in the request body using the `data` option. The `data` property accepts an object, which will be serialized into JSON and included in the request body. For example: `axios.post('/api/data', { name: 'John Doe', age: 30 })`. You can also use `withCredentials: true` if you need to send cookies along with the request.