If you want to export a mind map into a PDF or PNG file without a watermark, you need to upgrade to Xmind Pro Plan for Xmind Mobile.
After you subscribe to Xmind Pro Plan, you can sign in with your account on Xmind Mobile to unlock the Pro features.
Please follow these steps to export a PDF/PNG file without a watermark.
1. Open the map,
2. Tap “...” on the upper right corner,
3. Tap Export,
4. Select PDF or PNG or Markdown to export the mind map.