Nice to meet you, @LM91.
Let me help and share some information about handling a customer payment deposited into an old company when the invoice was issued by a new company in QuickBooks Desktop.
If both the old and new companies use the same bank account, the transition in company type should not impact the payment process. This allows seamless fund management regardless of the change in business structure. However, it's important to ensure that the transition from a Sole Proprietorship to an LLC is properly documented in all financial records for a smooth workflow on your QuickBooks Desktop.
You can also check this article to get more info about deposit times for QuickBooks Payments.
Furthermore, you can browse this link for future reference on what to do next after processing payments.
You can always tap me if you have additional questions handling a customer payment or any QuickBooks Desktop-related concerns. Take the best care always, and have a wonderful weekend ahead, @LM91!