Hi @Khiem Duy Tran ,  I've just enabled the beta for your account. In your left nav you will now see a section called "Newsletters". You are all set to send newsletters on Hub. Once you have used the tool, or, if you encounter any issues, I'd love to hear your feedback on it. You can schedule a quick zoom with me at https://calendly.com/woody-decilegroup, or just send feedback directly to developers@decilegroup.com.