Custom.vue

<template>
  <div class="q-pa-md q-gutter-sm">
    <q-editor
      v-model="editor"
      flat
      content-class="bg-amber-3"
      toolbar-text-color="white"
      toolbar-toggle-color="yellow-8"
      toolbar-bg="primary"
      :toolbar="[
        ['bold', 'italic', 'underline'],
        [{
          label: $q.lang.editor.formatting,
          icon: $q.iconSet.editor.formatting,
          list: 'no-icons',
          options: ['p', 'h3', 'h4', 'h5', 'h6', 'code']
        }]
      ]"
    />
  </div>
</template>

<script>
import { ref } from 'vue'

export default {
  setup () {
    return {
      editor: ref('Customize it.')
    }
  }
}
</script>