Hello lcheah,
It's a pleasure to see you in Community. Welcome! I can understand the benefit of being able to have supplier remittance forms sent automatically. However, this currently isn't available in QuickBooks Online. If you would like to see this in future updates, please don't hesitate to submit a suggestion to the Development Team. Recommendations are greatly appreciated in assisting with improving your overall customer experience with QuickBooks Online. In the interim, you'll select Save and Send, to email it to your customer.
If you have any other questions, feel free to reach out. We would be happy to help!