Hi there, @sumanta-sen80-gm.
Are you trying to send invoices to your customers using an SMS option in QuickBooks? If so, this feature isn't available in the program.
If you're referring to invoice reminders, there's no facility for that. All of the settings that you've set are basically programmed in QuickBooks.
For more info, you can check out this article: Send invoice reminders automatically or manually in QuickBooks Online.
The Community always has your back, so please let me know if you have any other questions. I'll be more than happy to help. Keep safe.
