App-bridge Modal - Not able to add any html tags in body

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I've added the Shopify app-bridge Modal by using this doc. https://shopify.dev/docs/api/app-bridge/previous-versions/actions/modal.

const modalOptions = {
  title: 'My Modal',
  message: 'Hello world!',
};

But how can I add my HTML tags means <div>, <span>, and more instead of the only text in the message field?