Hi there, Thaya.
It's a great idea to have the option to turn off reminders for specific customers. However, this is currently unavailable in QuickBooks.
The feature that automatically sends reminders can't exclude specific customers, as it applies to all invoices. When you enable this feature, reminders start for all customers as soon as you create an invoice based on the due date.
As an alternative, I suggest disabling the automatic reminder feature and sending reminders to your customers manually. This way, you can exclude any customers you don't want to receive reminders.
Here’s how to turn off automatic reminders in QuickBooks Advanced:
- Go to the Workflow automation window.
- Click on the My Workflows tab.
- Turn off the Get unsent invoice reminder.
- Click Disable to confirm.

For Plus, Simple Start, and Essentials, follow these steps:
- Go to Settings and select Account and settings.
- Select the Sales tab.
- In the Reminders section, turn off the Automatic invoice reminders.

You can then follow the steps from the Send invoice reminders manually section in this article: Send invoice reminders manually in QuickBooks Online.
Please keep me posted if you have any further questions.