Thank you for posting here in QuickBooks Community and for choosing QuickBooks Online as your new accounting software.
Yes, it is not possible to send an invoice to a client and have the option to click the Pay button to start entering their card details so they get charged every 30 days automatically. To do this, you'll need to make a recurring sales receipt in QuickBooks Online.
Go to the Gear ⚙ icon and select Recurring transactions.
Click the New button. Then, select the Transaction Type drop-down menu and choose Sales Receipt. Then, OK.
Enter a template name. This won’t appear on the transaction.
From the Type drop-down menu, select Scheduled. Choose the customer’s name from the Customer drop-down menu. Then, verify the email.
Set the interval. For example, if you need a sales receipt every first day of the month, the interval is Monthly on day 1st of every 1 month. Then, enter the start and end date.
Select the Payment method drop-down and choose Credit card type or Check.
Enter the line for the product or service and amount.
I'm also adding this article to further guide you in effectively managing your business using QBO: Help guide for QuickBooks Online. It contains topics about advanced accounting, banking, and payments to name a few.
Let me know if there's anything else you need help with. Know that I'm always here to help you anytime. Take care and keep safe!