React Intl with Hook

example.tsx

import React from 'react'
import { useIntl } from 'react-intl'

const AdminForm = () => {
  const intl = useIntl()

  return (
    <form>
      <label>
        <small>{intl.formatMessage({ id: 'admin/username.form.label' })}</small>
        <input />
      </label>
      <button type="submit">
        {intl.formatMessage({ id: 'admin/username.form.submit' })}
      </button>
    </form>
  )
}

export default AdminForm

I would recommend using this method when possible instead:

import { FormattedMessage } from 'react-intl'

// ....inside the return of your component
  <FormattedMessage id="admin/username.form.label" />

Also, there are many other components that can be used:
https://github.com/formatjs/react-intl/blob/master/docs/Components.md