Thanks for reaching out to us. I'm here to help you and share details of what will happen after cancellation.
If you will cancel your account but you paid already for the nextbilling cycle, you'll still be able to access it. The account will be canceled automatically after the next billing date.
Once canceled, you'll have read-only access to the data for a year before it'll be deleted permanently. Please check this article for more details: Cancel your QuickBooks Self-Employed subscription.
If you're subscribed to QuickBooks Payments, it will not affect your funds. You'll receive the money as scheduled. You can still get the data and log in to your Merchant account.
Need more references in using QuickBooks Self-Employed? Visit this page: QBSE Articles.
Leave a comment below if you have other questions. Take care!