Hi marcomiranda, 

Thanks for joining the thread. 

I understand how important it is to be able to pull up a report that will show you the frequency of a customer paying late or how long they typically take to pay their invoices. On the other hand, you can run an Invoices and Receive Payments report and export it in Excel file to be able to manually calculate the days it takes for your customer to pay. 

Feel free to send your valuable feedback by going to Gear icon and select Feedback to have this feature be added on the future releases of QuickBooks Online.