Hello there, @SPARKY14.
I'm happy to answer all your queries when you downgrade your subscription from QuickBooks Online (QBO) Plus to QBO Simple Start.
If you downgrade to Simple Start, it will not change anything about allowing clients to pay through the invoice as long as you have QuickBooks Payments. See this article for details: Take and process payments in QuickBooks Online with QuickBooks Payments.
Next, about receiving payments, there's still no way to create a rule that will add a 3% processing fee to an invoice if they do use a credit card. You'll still have to add it manually to their invoice.
Lastly, with regards to creating rules for the recurring monthly plan for your clients, you can set up a recurring invoice. I'll show you how.
- Create your invoice, then select Create recurring invoice on the transaction.
- Or you can create a recurring template.
- Specify the frequency interval, start date, and end date of the recurring invoice.
- Once finished, select Save template.
You can also set up automatic payments for recurring invoices. Check this article for details: Set up Autopay for recurring invoices in QuickBooks Online.
If you're ready to downgrade your subscription, you may visit this link for guidance: Upgrade or downgrade your QuickBooks Online edition.
If you have clarification or additional QuickBooks concerns, tag me in the comment below. I'm always here to assist you.
